Estate Finance Family Tax Planning Question

Uncle dies in 2019 and bequeaths Greenacre to Nephew. Uncles estate reports Greenacre with a fair market value of $1 million on his estate tax return, based on an appraisal obtained by Uncles estate. In 2020, nephew sells Greenacre for $2 million. Nephews basis in Greenacre is fair market value on the date of Uncles death. Even though Uncles estate tax return reported Greenacre with a fair market value of $1 million, Nephew cant believe that the property could be worth only $1 million in 2019, when he sold it the next year for twice that amount. So, Nephew hires his own appraiser who appraises Greenacre at $2 million as of Uncles death, attaches the appraisal to his income tax return and takes the position that he does not recognize income on the sale.

Assume that the appraisal obtained by Nephew showing the $2 million fair market value is more accurate than the appraisal obtained by Uncles estate and used to report Greenacres fair market value on Uncles estate tax return. Also assume that Uncles estate owed estate tax.

Can you, based on these facts, determine Nephews basis in Greenacre? If so, what is Nephews basis in Greenacre? Can Nephews basis in Greenacre differ from the value of Greenacre reported on Uncles estate tax return? Why or why not?