Supplemental Prospectus (Form 424B3)

PROSPECTUS

Filed pursuant to Rule 424(b)(3) Registration No. 333-288982

8,490,767 Shares of Common Stock

This prospectus relates to the resale by the selling stockholders named herein, including their transferees, assigns, pledgees or donees, or their respective successors, of up to 8,490,767 shares (the "Shares") of our common stock, par value $0.0001 per share (which we refer to as our common stock). The selling stockholders listed herein were the investors in a private placement by our company which closed on October 10, 2025. For information about the selling stockholders, see "Selling Stockholders."

We are not selling any securities under this prospectus and will not receive any of the proceeds from the sale of common stock by the selling stockholders. The selling stockholders may sell the Shares to or through underwriters, broker-dealers or agents, who may receive compensation in the form of discounts, concessions or commissions from the selling stockholders, the purchasers of the Shares, or both. We are registering the offer and sale of the Shares pursuant to certain registration rights granted to the selling stockholders. The timing and amount of any sale of Shares is within the sole discretion of the selling stockholders. We do not know when, or in what amount, the selling stockholders may offer the Shares for sale. We have paid the expenses of registering the Shares, including legal and accounting fees. All selling and other expenses incurred by the selling stockholders will be borne by the selling stockholders. See "Plan of Distribution" for additional information.

Our common stock is listed on The Nasdaq Capital Market under the symbol "NNE." On March 6, 2026, the last reported sale price of our common stock on The Nasdaq Capital Market was $23.54 per share.

We may amend or supplement this prospectus from time to time by filing amendments or supplements as required.

An investment in the securities offered through this prospectus is speculative and involves a high degree of risk. You should carefully consider the risk factors beginning on page 23 of this prospectus and the risk factors in our most recent Annual Report on Form 10-K, which is incorporated by reference herein, as well as the risk factors in our other recently filed quarterly and current reports incorporated by reference herein, and in the relevant prospectus supplements. We urge you to carefully read this prospectus and any documents incorporated by reference in this prospectus or any prospectus amendments or supplements before investing.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is March 13, 2026.

TABLE OF CONTENTS

	Page
About This Prospectus	ii
Cautionary Note Regarding Forward-Looking Statements	iii
Prospectus Summary	1
The Offering	22
Risk Factors	23
Use of Proceeds	23
Selling Stockholders	24
Plan of Distribution	26
Legal Matters	27
Experts	27
Where You Can Find More Information	27
Incorporation of Certain Information by Reference	27

ABOUT THIS PROSPECTUS

The information contained in this prospectus is not complete and may be changed. You should rely only on the information provided in or incorporated by reference in this prospectus, in any prospectus supplement or in a related free writing prospectus, or documents to which we otherwise refer you. We have not authorized anyone else to provide you with different information.

We have not authorized any dealer, agent or other person to give any information or to make any representation other than those contained or incorporated by reference in this prospectus and any accompanying prospectus supplement or any related free writing prospectus. You must not rely upon any information or representation not contained or incorporated by reference in this prospectus or an accompanying prospectus supplement or any related free writing prospectus. This prospectus and any accompanying prospectus supplement and any related free writing prospectus, if any, do not constitute an offer to sell or the solicitation of an offer to buy any securities other than the registered securities to which they relate, nor do this prospectus and any accompanying prospectus supplement and any related free writing prospectus, if any, constitute an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation in such jurisdiction. You should not assume that the information contained in this prospectus and any accompanying prospectus supplement and any related free writing prospectus, if any, is accurate on any date subsequent to the date set forth on the front of such document or that any information we have incorporated by reference is correct on any date subsequent to the date of the document incorporated by reference, even though this prospectus and any accompanying prospectus supplement and any related free writing prospectus is delivered or securities are sold on a later date.

We have not done anything that would permit this offering or possession or distribution of this prospectus or any free writing prospectus in any jurisdiction where action for that purpose is required, other than in the United States. You are required to inform yourself about and to observe any restrictions relating as to this offering and the distribution of this prospectus and any such free writing prospectus outside the United States.

We further note that the representations, warranties and covenants made by us in any agreement that is filed as an exhibit to any document that is incorporated by reference in this prospectus were made solely for the benefit of the parties to such agreement, including, in some cases, for the purpose of allocating risk among the parties to such agreements, and should not be deemed to be a representation, warranty or covenant to you. Moreover, such representations, warranties or covenants were accurate only as of the date when made. Accordingly, such representations, warranties and covenants should not be relied on as accurately representing the current state of our affairs.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

The information in this prospectus, any applicable prospectus supplement and any related free writing prospectuses, together with any information incorporated by reference in this prospectus and such prospectus supplement, contains "forward-looking statements" within the meaning of Section 27A of the Securities Act, and Section 21E of the Exchange Act. All statements other than statements of historical fact, including statements regarding our future operating results and financial position, our business strategy and plans, market growth, and our objectives for future operations, are forward-looking statements. These forward-looking statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.

You can identify some of these forward-looking statements by words or phrases such as "may," "will," "could," "would," "expect," "anticipate," "aim," "estimate," "intend," "plan," "believe," "is/are likely to," "potential," "project," "target," "continue" or the negative of these terms or other similar expressions, although not all forward-looking statements may contain these words. Forward-looking statements are only predictions and are based largely on our current expectations and projections about future events and financial trends that we reasonably believe may affect our business, financial condition and results of operations. Although we believe that the expectations reflected in our forward-looking statements are reasonable, actual outcomes could differ materially from those projected or assumed in any of our forward-looking statements. Our future business, financial condition and results of operations, as well as any forward-looking statements, are subject to change given the inherent risks and uncertainties of market and industry conditions.

Forward-looking statements are neither predictions nor guarantees of future outcomes. Forward-looking statements present estimates and assumptions only as of the date on the cover of the document in which they are contained, and are subject to significant known and unknown risks, uncertainties and assumptions. Accordingly, you are cautioned not to place undue reliance on forward-looking statements, which speak only as of the dates on which they are made. Important factors that could cause actual outcomes to differ materially from those in the forward-looking statements include, but are not limited to, those summarized below:

	●	Our ability to design, develop, manufacture, demonstrate, obtain regulatory approval for and ultimately sell our proposed nuclear reactors or other products, technologies or services we are developing.
	●	Our ability to source or internally develop the necessary fuel and material supply chain to power our next generation of advanced nuclear reactors.
	●	Our ability to source or internally develop the required transportation capabilities to move our reactors, their fuel, and other special materials critical to the commercial deployment of our reactor systems.
	●	Our ability to build internally, and to externally provide, nuclear service support and consultation services for the expanding and resurgent nuclear energy industry, both domestically and internationally.
	●	Our ability to source, retain, and expand our technical and business staff to meet the demands of our expanding and diversifying business.
	●	Our ability to raise the substantial amount of additional funds that will be necessary for our business to succeed, which funds may not be available on acceptable terms or available at all.
	●	The ability of key third party collaborators including, without limitation, The University of Illinois Urbana-Champaign, to perform their obligations to us and meet goals and timelines as expected.
	●	Assumptions relating to the size of the market for our nuclear reactors or other products, technologies or services we are developing.
	●	Our ability to navigate the complex and time-consuming nuclear regulatory regimes in the jurisdictions we operate, including unanticipated regulations or regulatory failures that could add barriers, time and cost to our business plans.
	●	Our estimates of future expenses, capital requirements, revenue potential and our needs for, or ability to obtain, additional financing.
	●	Our status as a pre-revenue company in a rapidly evolving, complex and highly competitive industry with a business model that is still being developed and is largely untested.
	●	Our ability to avoid a significant disruption in our information technology system, including security breaches, or our ability to implement new system and software successfully.
	●	Our ability to obtain and maintain intellectual property protection for our products.
	●	The other forward-looking statements regarding our company and its prospects included or incorporated by reference in this prospectus including, without limitation, those under "Risk Factors," "Management's Discussion and Analysis of Financial Condition and Results of Operations," and "Business" as such factors may be updated from time to time in our other filings with the SEC.

The foregoing does not represent an exhaustive list of matters that may be covered by the forward-looking statements contained herein or risk factors that we are faced with. Forward-looking statements necessarily involve risks and uncertainties, and our actual results could differ materially from those anticipated in the forward-looking statements due to a number of factors, including those set forth under "Risk Factors" and elsewhere contained or incorporated by reference in this prospectus. All written and oral forward-looking statements attributable to us or persons acting on our behalf are expressly qualified in their entirety by the cautionary statements contained above and throughout this prospectus. Prior to investing in our common stock, you should read this prospectus, our filings incorporated by reference herein and the documents we have filed as exhibits to this registration statement of which this prospectus is a part completely and with the understanding that our actual future results may be materially different from what we currently expect.

Except as required by law, we undertake no obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, after the date on which the statements are made or to reflect the occurrence of unanticipated events.

INDUSTRY AND MARKET DATA

Unless otherwise indicated, data concerning economic conditions, our industry, our markets and our competitive position are based on a variety of sources, including information from third-party industry analysts, publications, surveys and forecasts and our own estimates and research. These data involve a number of assumptions, estimates and limitations. Industry publications, surveys and forecasts and other public information generally indicate or suggest that their information has been obtained from sources believed to be reliable. None of the third-party industry data used in this prospectus were prepared on our behalf. The industry in which we operate is subject to a high degree of uncertainty and risk due to a variety of factors, including those described in "Risk Factors". These and other factors could cause results to differ materially from those expressed in these data.

TRADEMARKS

We own or have rights to trademarks or trade names that we use in connection with the operation of our businesses, our corporate names, logos and websites. We may make references to our trademarks and service marks, and to those belonging to other entities. Solely for convenience, trademarks and trade names referred to may appear without ® or ^™ or similar symbols, but such references are not intended to indicate, in any way, that we will not assert, to the fullest extent possible under applicable law, our rights or the rights of the applicable licensor to these trademarks and trade names. We do not intend our use or display of other companies' trade names, trademarks, or service marks to imply a relationship with, or an endorsement or sponsorship of us by, any other companies. All other trademarks and service marks are the property of their respective owners.

RISK FACTORS

Investing in our common stock is speculative and involves a high degree of risk. You should carefully consider the risks and uncertainties described under "Risk Factors" in our most recent Annual Report on Form 10-K as supplemented or updated in our most recent Quarterly Report on Form 10-Q, any current reports on Form 8-K, as well as any accompanying prospectus supplement, together with all of the other information included or incorporated by reference in this prospectus and in any accompanying prospectus supplement, including our financial statements and related notes, before deciding whether to purchase our common stock. See "Incorporation of Certain Information by Reference" for more information on the filings (including the risk factors) which are incorporated herein by reference.

Our business, financial condition and results of operations could be materially and adversely affected by any or all of these risks or by additional risks and uncertainties not presently known to us or that we currently deem immaterial that may materially and adversely affect us in the future.

USE OF PROCEEDS

We will not receive any proceeds from the sale of the Shares by the selling stockholders. The selling stockholders will pay any expenses incurred by the selling stockholders for brokerage, accounting, tax or legal services or any other expenses incurred by the selling stockholders in disposing of their shares of common stock. We will bear all other costs, fees and expenses incurred in effecting the registration of the Shares covered by this prospectus, including, without limitation, all registration fees and fees and expenses of our counsel and our accountants.

SELLING STOCKHOLDERS

The shares of common stock being offered by the selling stockholders listed below were issued by us in a private placement which closed on October 10, 2025. Other than the relationships as purchasers under the Securities Purchase Agreement (as defined below) and as otherwise described herein, to our knowledge, no material relationships exist between any of the selling stockholders and us nor have any such material relationships existed within the past three years.

As used herein, the term "selling stockholders" means the selling stockholders listed below and such holders' donees, pledgees, transferees, or other successors-in-interest selling shares of common stock or warrant shares received after the date of this prospectus from a selling stockholder as a gift, pledge, partnership distribution or other transfer.

Summary of October 2025 Private Placement

On October 7, 2025, we entered into a Securities Purchase Agreement (the "Securities Purchase Agreement") with six institutional investors, who are the selling stockholders hereunder (the "Investors"), pursuant to which we agreed to offer and sell 8,490,767 Shares in a private placement for gross proceeds of approximately $400,000,000. Pursuant to the Securities Purchase Agreement, we issued and sold the Shares in the private placement at a purchase price of $47.11 per share. The private placement closed on October 10, 2025. After deducting the placement agent fees and estimated offering expenses payable by us, we received net proceeds of approximately $378,600,000.

Pursuant to the Securities Purchase Agreement, we agreed to include a resale prospectus in the next amendment to its registration statement on Form S-3 initially filed with the Securities and Exchange Commission (the "SEC") on July 25, 2025 (File No. 333-288982) covering the resale of the Shares as soon as practicable but no later than October 25, 2025 (the date of filing, the "Filing Date"), and with such registration statement to be effective within 30 days following the later of (i) the Filing Date, and (ii) the second business day after the date on which the United States Federal government shutdown has concluded and the SEC has reopened for operations, if it is not subject to review by the SEC. We will have an additional 30 days to cause such registration statement to become effective if it is subject to full review by the SEC. We have filed the registration statement of which this prospectus forms a part in satisfaction of the foregoing Investor registration rights.

Titan Partners Group LLC, a division of American Capital Partners, LLC, acted as placement agent for the private placement and for services rendered received a cash fee equal to 5.0% of the gross proceeds received by us in the private placement, and reimbursement of $200,000 in legal expenses.

Selling Stockholders Table

The table below lists the selling stockholders and other information regarding the beneficial ownership of the shares of common stock by each of the selling stockholders. The table below sets forth information as of the date of this prospectus, to our knowledge, about the beneficial ownership of our common stock by the selling stockholders both before and immediately after this offering. Because the selling stockholders may sell, transfer, or otherwise dispose of all, some, or none of their shares of common stock, we cannot determine the number of such shares that will be sold, transferred or otherwise disposed of by the selling stockholders, or the amount or percentage of shares of our common stock that will be held by the selling stockholders upon termination of any particular offering. See "Plan of Distribution." For purposes of the table below, we assume that the selling stockholders will sell all of their shares of common stock.

		Shares of Common Stock Beneficially Owned Before Completion of the Offering (1)								Sum of Number of Shares of Common Stock				Shares of Common Stock Beneficially Owned After Completion of the Offering (1)
Name		Number of Shares				Percentage				Offered Hereby (2)				Number of Shares				Percentage
Blackstone Global Master Fund ICAV (2)			2,122,692				4.19	%			2,122,692				-				-
Citadel CEMF Investments Ltd. (3)			1,199,443				2.37	%			1,199,443				-				-
Point72 Associates, LLC (4)			711,000				1.41	%			711,000				-				-
Regal Funds Management Pty Limited (5)			1,273,614				2.52	%			1,273,614				-				-
Weiss Asset Management and affiliates (6)			1,594,795				3.15	%			1,592,018				2,777				*
Ghisallo Master Fund LP (7)			1,592,000				3.15	%			1,592,000				-				-
TOTAL											8,490,767				2,777				*

*	Less than 1%.
(1)	Applicable percentages based on 52,083,194 shares of common stock outstanding as of March 6, 2026.
(2)	Consists of (i) 1,592,019 shares held directly by Blackstone Aqua Master Sub-Fund (the "Aqua Fund"), a sub-fund of Blackstone Global Master Fund ICAV and (ii) 530,673 held directly by BSOF Liquid Investments L.P. ("BSOF"). Blackstone Alternative Solutions L.L.C. is the investment manager of each of the Aqua Fund and BSOF. Blackstone Holdings I L.P. is the sole member of Blackstone Alternative Solutions L.L.C. Blackstone Holdings I/II GP L.L.C. is the general partner of Blackstone Holdings I L.P. Blackstone Inc. is the sole member of Blackstone Holdings I/II GP L.L.C. Blackstone Group Management L.L.C. is the sole holder of the Series II preferred stock of Blackstone Inc. Blackstone Group Management L.L.C. is wholly owned by its senior managing directors and controlled by its founder, Stephen A. Schwarzman. Each of such Blackstone entities and Mr. Schwarzman may be deemed to beneficially own the securities beneficially owned by the Aqua Fund and BSOF directly or indirectly controlled by it or him, but each (other than the Aqua Fund and BSOF to the extent of each of its direct holdings) disclaims beneficial ownership of such securities. The address of each of the entities listed is c/o Blackstone Inc., 345 Park Avenue, New York, NY 10154.
(3)	Consists of 1,199,443 shares of common stock purchased by Citadel CEMF Investments Ltd., or Citadel CEMF, in connection with the private placement. Citadel Advisors LLC is the portfolio manager of Citadel CEMF. Citadel Advisors Holdings LP, or CAH, is the sole member of Citadel Advisors LLC. Citadel GP LLC, or CGP, is the general partner of CAH. Kenneth Griffin owns a controlling interest in CGP. Mr. Griffin, as the owner of a controlling interest in CGP, may be deemed to have shared power to vote or direct the vote of, and/or shared power to dispose or to direct the disposition over, the securities held by Citadel CEMF. This disclosure is not and shall not be construed as an admission that Mr. Griffin or any of the Citadel CEMF related entities listed above is the beneficial owner of any securities of the Company other than the securities actually owned by such person (if any). The address of Citadel CEMF is c/o Citadel Enterprise Americas LLC, Southeast Financial Center, 200 S. Biscayne Blvd., Suite 3300, Miami, FL 33131.
(4)	Point72 Asset Management, L.P. maintains investment and voting power with respect to the securities held by certain investment funds it manages, including Point72 Associates, LLC. Point72 Capital Advisors, Inc. is the general partner of Point72 Asset Management, L.P. Mr. Steven A. Cohen controls each of Point72 Asset Management, L.P. and Point72 Capital Advisors, Inc. By reason of the provisions of Rule 13d-3 of the Exchange Act, each of Point72 Asset Management, L.P., Point72 Capital Advisors, Inc., and Mr. Cohen may be deemed to beneficially own the securities held by Point72 Associates, LLC that are disclosed herein. Each of Point72 Asset Management, L.P., Point72 Capital Advisors, Inc., and Mr. Cohen disclaims beneficial ownership of any such securities.
(5)	Regal Funds Management Pty Ltd. is controlled by Regal Partners Limited. Philip King has voting and dispositive power with respect to the securities held by this selling stockholder. Mr. King disclaims beneficial ownership of the shares held by this selling stockholder, except to the extent of his pecuniary interest therein. The address of the selling stockholder is Level 46, Gateway, 1 Macquarie Place, Sydney NSW 2000.
(6)	Shares offered hereby consists of (i) 955,211 shares held by Brookdale Global Opportunity Fund ("BGO") and (ii) 636,807 shares held by Brookdale International Partners, L.P. ("BIP"). Andrew Weiss is the Manager of WAM GP LLC, which is the general partner of Weiss Asset Management LP, the investment manager of BGO and BIP. WAM GP LLC is also the Manager of BIP GP LLC, the general partner of BIP. Mr. Weiss has voting and dispositive power with respect to the securities held by BGO and BIP. Mr. Weiss, WAM GP LLC, Weiss Asset Management LP and BIP GP LLC each disclaim beneficial ownership of the shares held by BGO and BIP, except to the extent of their respective pecuniary interests therein. The business address of the foregoing entities is c/o Weiss Asset Management, 222 Berkeley Street, 16th Floor, Boston, MA 02116.
(7)	Ghisallo Master Fund LP ("Ghisallo") is the beneficial owner of the shares of common stock. Ghisallo Capital Management LLC ("Ghisallo Capital") is the investment manager of Ghisallo and has voting control over the securities. The securities held by Ghisallo may be deemed to be beneficially owned by Ghisallo Capital and Michael Germino. Notwithstanding the foregoing, Mr. Germino disclaims beneficial ownership of the shares of common stock except to the extent of his pecuniary interest therein. The address of the selling stockholder is c/o Walkers Corporate, 190 Elgin Avenue, George Town Grand Cayman, CI KY 1-9008.

PLAN OF DISTRIBUTION

We are registering the Shares on behalf of the selling stockholders to permit the resale of such shares by the selling stockholders from time to time after the date of this prospectus. The Shares were purchased from us by the selling stockholders in a private placement which closed on October 10, 2025. We will not receive any of the proceeds from the sale of the Shares by the selling stockholders. We will bear all fees and expenses incident to our obligation to register the shares of common stock.

The selling stockholders, which may include donees, pledgees, transferees or other successors-in-interest selling shares of common stock or interests in shares of common stock received after the date of this prospectus from a selling stockholders as a gift, pledge, partnership distribution or other transfer, may sell all or a portion of the shares of common stock beneficially owned by them and offered hereby from time to time on any stock exchange, market or trading facility on which the shares are traded or in private transactions.

A selling stockholder may use any one or more of the following methods when disposing of shares or interests therein:

	●	ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers;
	●	block trades in which the broker-dealer will attempt to sell the shares as agent, but may position and resell a portion of the block as principal to facilitate the transaction;
	●	purchases by a broker-dealer as principal and resale by the broker-dealer for its own account;
	●	an exchange distribution in accordance with the rules of the applicable exchange;
	●	privately negotiated transactions;
	●	through the writing or settlement of options or other hedging transactions, whether through an options exchange or otherwise;
	●	through agreements between broker-dealers and the selling stockholders to sell a specified number of such shares at a stipulated price per share;
	●	a combination of any such methods of sale; and
	●	any other method permitted by applicable law.

The selling stockholders may, from time to time, pledge or grant a security interest in some or all of the shares of Shares owned by them and, if they default in the performance of their secured obligations, the pledgees or secured parties may offer and sell the Shares, from time to time, under this prospectus, or under an amendment to this prospectus under Rule 424(b) or other applicable provision of the Securities Act amending the list of selling stockholders to include the pledgee, transferee or other successors in interest as selling stockholders under this prospectus. The selling stockholders also may transfer the Shares in other circumstances, in which case the pledgees, transferees or other successors in interest will be the selling beneficial owners for purposes of this prospectus.

The selling stockholders also may resell all or a portion of the Shares in open market transactions in reliance upon Rule 144 under the Securities Act, as permitted by that rule, or Section 4(a)(1) under the Securities Act, if available, rather than under this prospectus; provided that they meet the criteria and conform to the requirements of those provisions.

In connection with the sale of the Shares or interests therein, the selling stockholders may enter into hedging transactions with broker-dealers or other financial institutions, which may in turn engage in short sales of our common stock in the course of hedging the positions they assume. The selling stockholders may also sell our common stock short and deliver the Shares to close out their short positions, or loan or pledge the Shares to broker-dealers that in turn may sell the Shares. The selling stockholders may also enter into options or other transactions with broker-dealers or other financial institutions or the creation of one or more derivative securities which require the delivery to each such broker-dealer or other financial institution of Shares offered by this prospectus, which shares such broker-dealer or other financial institution may resell pursuant to this prospectus (as supplemented or amended to reflect such transaction).

The aggregate proceeds to the selling stockholders from the sale of the Shares offered by them will be the purchase price of the Shares, less discounts or commissions, if any. The selling stockholders reserve the right to accept and, together with their agents from time to time, to reject, in whole or in part, any proposed purchase of Shares to be made directly or through agents.

The selling stockholders and any underwriters, broker-dealers or agents that participate in the sale of the Shares or interests therein may be "underwriters" within the meaning of Section 2(a)(11) of the Securities Act. Any discounts, commissions, concessions or profit they earn on any resale of the Shares may be underwriting discounts and commissions under the Securities Act. If the selling stockholders is an "underwriter" within the meaning of Section 2(a)(11) of the Securities Act, they will be subject to the prospectus delivery requirements of the Securities Act.

To the extent required, the Shares to be sold, the name of the selling stockholder, the respective purchase prices and public offering prices, the names of any agents, dealer or underwriter, and any applicable commissions or discounts with respect to a particular offer will be set forth in an accompanying prospectus supplement or, if appropriate, a post-effective amendment to the registration statement that includes this prospectus.

If underwriters are used in the sale, the Shares will be acquired by the underwriters for their own account and may be resold from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. In connection with any such underwritten sale of Shares, underwriters may receive compensation from the selling stockholder, for whom they may act as agents, in the form of discounts, concessions or commissions. If the selling stockholders use an underwriter or underwriters to effectuate the sale of Shares, we and/or the applicable selling stockholder will execute an underwriting agreement with those underwriters at the time of sale of those Shares.

To the extent required by law, the names of the underwriters will be set forth in a prospectus supplement or, if appropriate, a post-effective amendment to the registration statement that includes the prospectus supplement and the accompanying prospectus used by the underwriters to sell those securities. The obligations of the underwriters to purchase those Shares will be subject to certain conditions precedent, and unless otherwise specified in a prospectus supplement, the underwriters will be obligated to purchase all the Shares offered by such prospectus supplement if any of such Shares are purchased. Any public offering price and any discounts or concessions allowed or re-allowed or paid to dealers may be changed from time to time.

The selling stockholders may indemnify any broker-dealer that participates in transactions involving the sale of the Shares against certain liabilities, including liabilities arising under the Securities Act.

Listing

Our common stock is listed on The Nasdaq Capital Market under the trading symbol "NNE."

LEGAL MATTERS

The validity of the issuance of the common stock offered by this prospectus has been passed upon for us by Parsons Behle & Latimer, Reno, Nevada.

EXPERTS

The consolidated financial statements of Nano Nuclear Energy, Inc. and its consolidated subsidiaries, as of and for the fiscal years ended September 30, 2025 and 2024, incorporated in this prospectus by reference to our 2025 Annual Report on Form 10-K for the fiscal year ended September 30, 2025, have been so incorporated in reliance on the report of WithumSmith+Brown, PC, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

WHERE YOU CAN FIND MORE INFORMATION

This prospectus is part of the registration statement on Form S-3 that we have filed with the SEC under the Securities Act and does not contain all the information set forth or incorporated by reference in the registration statement. Whenever a reference is made in this prospectus to any of our contracts, agreements or other documents, the reference may not be complete and you should refer to the exhibits that are a part of the registration statement, or to the exhibits to the reports or other documents incorporated by reference in this prospectus, for a copy of such contract, agreement or other document. We file annual, quarterly and periodic reports, proxy statements and other information with the SEC, using its EDGAR system. The SEC provides free public access, through its website, to items publicly filed in the EDGAR system, including our items. The address of the SEC's website is https://www.sec.gov.

We also maintain a website at www.nanonuclearenergy.com. You may access these materials at our website free of charge as soon as reasonably practicable after they are electronically filed with, or furnished to, the SEC. Information contained in, or that can be accessed through, our website is not a part of, and is not incorporated into, this prospectus.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

We are "incorporating by reference" in this prospectus certain documents we have filed or will file with the SEC, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus, and later information that we file with the SEC will automatically update and supersede this information. We incorporate by reference the documents listed below and any future filings made with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (1) after the date of the initial registration statement, as amended, and prior to effectiveness of the registration statement, and (2) after the date of this prospectus and prior to the termination of this offering, from their respective filing dates (other than any portions thereof, which under the Exchange Act, and applicable SEC rules, are not deemed "filed" under the Exchange Act). Such information will automatically update and supersede the information contained in this prospectus and the documents listed below:

1. Our Annual Report on Form 10-K for the fiscal year ended September 30, 2025, filed with the SEC on December 18, 2025 (the "2025 Annual Report");

2. Our Current Reports on Form 8-K filed with the SEC on October 10, 2025, October 22, 2025, and February 5, 2026, respectively (excluding any information therein disclosed under Items 2.02 or 7.01 or any corresponding information furnished under Item 9.01 or included as an exhibit);

3. Our quarterly report ("Quarterly Report") on Form 10-Q filed with the SEC on February 17, 2026; and

4. The description of our shares of common stock contained in our registration statement on Form 8-A, filed with the SEC on May 6, 2024.

In addition, all documents and/or reports that we file with the SEC pursuant to Sections 13(a), 13(c), 14, and 15(d) of the Exchange Act subsequent to the date of the registration statement of which this prospectus is a part, and prior to the termination or completion of any applicable offering of securities under this prospectus or the filing of a post-effective amendment to such registration statement that indicates that all securities offered under this prospectus have been sold, or that deregisters all securities then remaining unsold, will be deemed to be incorporated herein by reference and to be a part hereof from the date of filing of such documents.

Notwithstanding the foregoing, none of the information that we disclose under Items 2.02 or 7.01 of any Current Report on Form 8-K, or any corresponding information furnished under Item 9.01 or included as an exhibit, that we may from time to time furnish to the SEC, will be incorporated by reference in, or otherwise included in, this prospectus, except as otherwise expressly set forth in the relevant document. Subject to the foregoing, all information appearing in this prospectus is qualified in its entirety by the information appearing in the documents incorporated by reference.

You may request, orally or in writing, a copy of the documents we incorporate by reference, which will be provided to you at no cost (other than exhibits, unless such exhibits are specifically incorporated by reference), by contacting our Secretary, c/o Nano Nuclear Energy Inc. at 10 Times Square, 30th Floor, New York, NY 10018. Our telephone number is (212) 634-9206.

8,490,767 Shares of Common Stock

Offered by the Selling Stockholders

PROSPECTUS

March 13, 2026