Nebraska Revised Statute 77-2775
(1) If the amount of a taxpayer's federal adjusted gross income, taxable income, or tax liability reported on his or her federal income tax return for any taxable year is changed or corrected by the Internal Revenue Service or other competent authority or as the result of a renegotiation of a contract or subcontract with the United States, the taxpayer shall report such change or correction in federal adjusted gross income, taxable income, or tax liability within sixty days after the final determination of such change, correction, or renegotiation.
(2) Whenever the amount of a taxpayer's income which is taxable in any state for any taxable year or any tax credits allowable in such state are changed or corrected in a way material to the tax liability owed to this state by the agency having authority to examine returns filed with such state or any other competent authority or whenever an amended return is filed by any taxpayer with a change or correction material to the tax liability owed to this state with another state, such change or correction shall be reported to the Tax Commissioner within sixty days after the final change or correction or filing of the amended return. The Tax Commissioner shall by rule and regulation provide the nature of any change or correction which must be reported.
(3) The taxpayer shall report all changes or corrections required to be reported under this section by filing an amended income tax return and shall give such information as the Tax Commissioner may require. The taxpayer shall concede the accuracy of any change or correction or state why it is erroneous.
(4) Any taxpayer filing an amended federal income tax return shall also file within sixty days thereafter an amended income tax return under the Nebraska Revenue Act of 1967 and shall give such information as the Tax Commissioner may require. For any amended federal income tax return requesting a credit or refund, the amended Nebraska income tax return shall be filed within sixty days after the taxpayer has received proof of federal acceptance of the credit or refund or within the time for filing an amended Nebraska income tax return that would otherwise be applicable notwithstanding the amended federal income tax return, whichever is later.