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