why do you think it's nontaxable? generally, an RMD is fully taxable unless you have a tax basis in it or you made a direct contribution to a qualified charity (QCD). many times box 2 is left blank solely because the Trustee doesn't know whether you treated the contributions as non-deductible or deductible. if you took the non-deductible option there should be form 8606 which will reflect your tax basis from which Tyrbotax will compute the taxable and non-taxable portions. the only other exception i could think of is a distribution from an inherited Roth IRA.
