Neb. Rev. Stat. § 77-2760

(1) For purposes of the income tax imposed by the provisions of the Nebraska Revenue Act of 1967, a taxpayer's method of accounting shall be the same as his method of accounting for federal income tax purposes. (2) If a taxpayer's method of accounting is changed for federal income tax purposes, his method of accounting for purposes of the income tax provisions of the Nebraska Revenue Act of 1967 shall similarly be changed.