Neb. Rev. Stat. § 77-2777: Income tax; deficiency; notice.

Sixty days after the date on which it was mailed, or one hundred fifty days if the taxpayer is outside the United States, a notice of proposed assessment of a deficiency shall constitute a final assessment of the amount of tax specified together with interest, additions to tax, and penalties except only for such amounts as to which the taxpayer has filed a protest with the Tax Commissioner.