SEC Form 40-F filed by Nexgen Energy Ltd.

RESOURCE AND RESERVES ESTIMATES

Unless otherwise indicated, all resource and reserve estimates included in the documents incorporated by reference into this Annual Report have been prepared in accordance with Canadian National Instrument 43-101 (“NI 43-101”) and the Canadian Institute of Mining and Metallurgy Classification System. Canadian standards, including NI 43-101, differ significantly from the requirements of the United States Securities and Exchange Commission (the “SEC” or the “Commission”), and resource information contained in the documents incorporated by reference into this Annual Report may not be comparable to similar information disclosed by U.S. companies. Accordingly, information concerning mineral deposits in this Annual Report may not be comparable with information made public by companies that report in accordance with United States standards.

ADDITIONAL DISCLOSURE

Certifications and Disclosure Regarding Controls and Procedures.

It should be noted that while NexGen’s principal executive officer and principal financial officer believe that NexGen’s disclosure controls and procedures provide a reasonable level of assurance that they are effective, they do not expect that NexGen’s disclosure controls and procedures or internal control over financial reporting will prevent all errors or fraud. A control system, no matter how well conceived or operated, can provide only reasonable, not absolute, assurance that the objectives of the control system are met.

Notices Pursuant to Regulation BTR

None.

Audit Committee Financial Expert

NexGen’s board of directors has determined that each of Trevor Thiele, Sybil Veenman, and Richard Patricio, members of NexGen’s audit committee, is “independent” as that term is defined in the rules of the NYSE New York Stock Exchange (“NYSE”) and that Mr. Thiele qualifies as an “audit committee financial expert” (as such term is defined in Form 40-F).

Code of Ethics

NexGen has adopted a Code of Ethics that meets the definition of a “code of ethics” set forth in Form 40-F, and that applies to NexGen’s principal executive officer, principal financial officer, principal accounting officer or controller, and persons performing similar functions.

The Code of Ethics is available for viewing on NexGen’s website at http://www.nexgenenergy.ca/corporate/corporate-governance/, and is available in print to any shareholder who requests it. Requests for copies of the Code of Ethics should be made by contacting: Investor Relations by phone at (604) 428-4112 or by e-mail at [email protected].

If any amendment to the Code of Ethics is made, or if any waiver from the provisions thereof is granted, NexGen may elect to disclose the information about such amendment or waiver required by Form 40-F to be disclosed, by posting such disclosure on NexGen’s website, which may be accessed at www.nexgenenergy.ca.

Principal Accountant Fees and Services

The required disclosure is included under the headings “Audit Committee Disclosure – External Auditor Service Fees (By Category)” in NexGen’s Annual Information Form for the fiscal year ended December 31, 2024, filed as Exhibit 99.1 to this Annual Report.

Pre-Approval Policies and Procedures.

Off-Balance Sheet Arrangements

NexGen does not have any off-balance sheet arrangements that have or are reasonably likely to have a current or future effect on its financial condition, changes in financial condition, revenues or expenses, results of operations, liquidity, capital expenditures or capital resources that is material to investors.

Cash Requirements

The required disclosure is included under the headings “Liquidity and Capital Resources” and “Contractual Obligations and Commitments” in NexGen’s Management’s Discussion and Analysis for the year ended December 31, 2024, filed as Exhibit 99.2 to this Annual Report on Form 40-F.

Identification of the Audit Committee.

We have a separately designated standing audit committee established in accordance with Section 3(a)(58)(A) of the Exchange Act. The members of the audit committee are Sybil Veenman, Richard Patricio, and Trevor Thiele.

Mine Safety Disclosure

Not applicable.

Disclosure Regarding Foreign Jurisdictions that Prevent Inspections

Not applicable.

Recovery of Erroneously Awarded Compensation

Not applicable.

NYSE Statement of Governance Differences

As a Canadian corporation listed on the NYSE, we are not required to comply with certain NYSE corporate governance standards, so long as we comply with Canadian and TSX corporate governance requirements. In order to claim such an exemption, however, we are required to disclose any significant differences between our corporate governance practices and those required to be followed by U.S. domestic issuers under the NYSE corporate governance standards. We have prepared a summary of the significant ways in which our corporate governance practices differ from those required to be followed by U.S. domestic companies under the NYSE’s corporate governance standards, and that summary is available for viewing on our website at:

http://www.nexgenenergy.ca/_resources/governance/Statement-of-Significant Differences.pdf

UNDERTAKING AND CONSENT TO SERVICE OF PROCESS

We undertake to make available, in person or by telephone, representatives to respond to inquiries made by the Commission staff, and to furnish promptly, when requested to do so by the Commission staff, information relating to: the securities registered pursuant to Form 40-F; the securities in relation to which the obligation to file an annual report on Form 40-F arises; or transactions in said securities.

We have previously filed a Form F-X in connection with the class of securities in relation to which the obligation to file this report arises.

Any change to the name or address of our agent for service shall be communicated promptly to the Commission by an amendment to the Form F-X referencing our file number.

EXHIBITS

SIGNATURES

Pursuant to the requirements of the Exchange Act, the registrant certifies that it meets all of the requirements for filing on Form 40-F and has duly caused this annual report to be signed on its behalf by the undersigned, thereunto duly authorized, on March 3, 2025.