DELIVERY OF THIS INSTRUMENT TO AN ADDRESS, OTHER THAN AS SET FORTH ABOVE, DOES NOT CONSTITUTE A VALID DELIVERY (Form 8-K)

DELIVERY OF THIS INSTRUMENT TO AN ADDRESS, OTHER THAN AS SET FORTH ABOVE, DOES NOT CONSTITUTE A VALID DELIVERY.

The New York Stock Exchange (the "NYSE") member firm or bank or trust company which completes this form must communicate this guarantee and the number of Common Shares subscribed for in connection with this guarantee (separately disclosed as to the primary subscription and the over-subscription privilege) to the Subscription Agent and must deliver this Notice of Guaranteed Delivery, to the Subscription Agent, prior to 5:00 p.m., Eastern time, on the Expiration Date, guaranteeing delivery of (a) a properly completed and signed Subscription Certificate (which certificate must then be delivered to the Subscription Agent no later than the close of business of the first business day after the Expiration Date). Failure to do so will result in a forfeiture of the Rights.

GUARANTEE

The undersigned, a member firm of the NYSE or a bank or trust company having an office or correspondent in the United States, guarantees delivery to the Subscription Agent by no later than 5:00 p.m., Eastern time, on the first Business Day after the Expiration Date (August 14, 2025) unless extended, as described in the Prospectus) of a properly completed and executed Subscription Certificate, as subscription for such Common Shares is indicated herein or in the Subscription Certificate. Participants should notify the Depositary prior to covering through the submission of a physical security directly to the Depositary based on a guaranteed delivery that was submitted via the PTOP platform of The Depository Trust Company ("DTC").

Method of delivery of the Notice of Guaranteed Delivery (circle one)

A. Through DTC

B. Direct to Equiniti Trust Company, LLC, as Subscription Agent.

Please reference below the registration of the Rights to be delivered.

PLEASE ASSIGN A UNIQUE CONTROL NUMBER FOR EACH GUARANTEE SUBMITTED. This number needs to be referenced on any direct delivery of Rights or any delivery through DTC.

BENEFICIAL OWNER LISTING CERTIFICATION
NXG NextGen Infrastructure Income Fund

The undersigned, a bank, broker or other nominee holder of Rights ("Rights") to purchase common shares of beneficial interest, $0.001 par value per share ("Common Shares"), of NXG NextGen Infrastructure Income Fund (the "Fund") pursuant to the rights offering (the "Offer") described and provided for in the Fund's Prospectus Supplement, dated July 21, 2025, and the accompanying Prospectus, dated July 9, 2025 (collectively the "Prospectus"), hereby certifies to the Fund and to Equiniti Trust Company, LLC, as Subscription Agent for such Offer, that for each numbered line filled in below, the undersigned has exercised, on behalf of the beneficial owner thereof (which may be the undersigned), the number of Rights specified on such line pursuant to the primary subscription (as specified in the Prospectus) and such beneficial owner wishes to subscribe for the purchase of additional Common Shares pursuant to the over-subscription privilege (as defined in the Prospectus, in the amount set forth in the third column of such line.

Provide the following information, if applicable: