Nev. Rev. Stat. § 375A.180 — Determination of deficiency: Generally

1.  In a case not involving a false or
fraudulent return or failure to file a return, if the Department determines at
any time after the tax is due, but not later than 4 years after the return is
filed unless a longer period is provided by federal law, that the tax disclosed
in any return required to be filed by NRS
375A.015 to 375A.345 , inclusive,
is less than the tax disclosed by its examination, a deficiency must be
determined. That determination may also be made within such time after the
expiration of the period as may be agreed upon in writing between the
Department and the personal representative.
2.  For purposes of this section, a return
filed before the last day prescribed by law for filing that return must be
considered as filed on that last day.