Neb. Rev. Stat. §§ 77-27,125
If any tax, report, claim, statement, notice, petition, or other document including, to the extent authorized by the Tax Commissioner, a return of estimated tax, required to be filed within a prescribed period or on or before a prescribed date under the authority of any provision of the Nebraska Revenue Act of 1967 is, after such period or such date, delivered by United States mail to the Tax Commissioner, or the officer or person with which or with whom such document is required to be filed, the date of the United States postmark stamped on the envelope shall be deemed to be the date of delivery. This section shall apply only if the postmark date falls within the prescribed period or on or before the prescribed date for the filing of such document, determined with regard to any extension granted for such filing, and only if such document was deposited in the mail, postage prepaid, properly addressed to the Tax Commissioner. If any document is sent by United States registered mail, such registration shall be prima facie evidence that such document was delivered to the Tax Commissioner. To the extent that the Tax Commissioner shall prescribe by regulation, certified mail may be used in lieu of registered mail under this section. The provisions of this section shall apply in the case of postmarks not made by the United States post office only if and to the extent provided by regulations of the Tax Commissioner. When the last day prescribed under the authority of the Nebraska Revenue Act of 1967, including any extension of time, for performing any act falls on Saturday, Sunday, or a day considered a holiday by the Tax Commissioner's office, the performance of such act shall be considered timely if it is performed on the next succeeding day which is not a Saturday, Sunday, or a day considered a holiday by the Tax Commissioner's office. The Tax Commissioner shall, upon request, give a receipt for any document filed under the provisions of the Nebraska Revenue Act of 1967.
Neb. Rev. Stat. §§ 77-27,125