Neb. Rev. Stat. § 77-7013

(1) A taxpayer shall claim the tax credit by attaching the tax credit certification received from the department under section 77-7012 to the taxpayer's tax return. (2) Any credit in excess of the taxpayer's tax liability shall be refunded to the taxpayer. In lieu of claiming a refund, the taxpayer may elect to have the excess carried forward to subsequent taxable years. A taxpayer may carry forward the excess tax credits until fully utilized.