I think that the NUA amount needs to be entered on TurboTax's Form 8960 Worksheet, Line 5b Adjustments for gain or loss on dispositions, and I think this can only be done in forms mode of the download version of TurboTax. I can't find anywhere to make this entry in step-by-step mode of the download version of TurboTax and I suspect it can't be done in the online version of TurboTax either.
