there can be several issues involved. first is the NOL year a closed year. an amended return cannot be filed for a closed year. if the NOL year is not a closed year amended returns would be filed for the NOL tear and each subsequent year it was used. Second did the NOL arise in a year in which a carryback was allowed and was done (in those years there may have been a provision to waive the NOL c/b)
Rev Rul 81-88.
"In determining the amount of a net operating loss that may be carried from a closed year forward to an open year, the special rules of section 301.6511(d)-2(a)(3) of the regulations do not apply. Since the net operating loss for the closed year is based upon items arising in the closed year, all adjustments to taxable income, whether or not barred by the statute of limitations, will be taken into account and the amount of net operating loss carryover will be determined under the rules of section 172 of the Code."
in short, the c/f must be adjusted. this would require amended any c/f year that is still open in which the NOL was used.
there is a blog about NOL's c/f & c/b, its over 200 pages long. I don't expect you to read it just providing a reference. it's from 2014 and part of it deals with NOL c/bs which are not allowed under current law.
https://www.millerchevalier.com/sites/default/files/resources/Reprints/NYLS-Review_Net-Operating-Los...
"In the context of carryovers, courts have made clear that taxpayers and the IRS
may adjust the amount of an NOL to reflect time-barred adjustments in the loss
year. The same is true when the time-barred adjustment occurs after the loss year.
Courts achieve that result by interpreting § 172(b)(2)’s reference to “taxable income”
to mean correct taxable income."
