Neb. Rev. Stat. §§ 77-4311
Notice of a determination that the tax imposed by section 77-4303 is due and owing shall be personally served or mailed to the dealer within six years after the Tax Commissioner knows or has information available to make such determination. A determination that a dealer does not possess an official stamp, label, or other indicium showing that the tax imposed by section 77-4303 has been paid or has not paid the tax imposed by section 77-4303 shall be considered a jeopardy determination. In any proceedings in court brought to enforce payment of taxes and applicable penalties under sections 77-4301 to 77-4316, a jeopardy determination, made with or without notice to the dealer, shall be for all purposes prima facie evidence of the dealer's failure to pay such taxes.
Neb. Rev. Stat. §§ 77-4311