Exhibit 99.1 Condensed Interim Consolidated Financial Statements For the three and nine months ended September 30, 2023 (expressed in thousands of Canadian dollars) - Unaudited NexGen Energy Ltd. Condensed Interim Consolidated Statements of Financial Position (expressed in thousands of Canadian Dollars) - Unaudited As at September 30, 2023 As at December 31, 2022 Assets Current assets Cash $ 370,444 $ 134,447 Marketable securities (Note 5) 7,240 5,775 Amounts receivable 1,546 1,801 Prepaid expenses and othe ...