You are talking about the estate tax deduction for receipt of Income in Respect of Decedent a miscellaneous deduction not subject to the 2% limitation. In TurboTax go to Deductions & Credits -> Other Deductions & Credits -> Other Deductible Expenses, then answer Yes on the page that asks "Did you have any of these other expenses." Enter the amount in the box labeled "Estate tax deduction not reported on an estate K-1."
This deduction on your personal tax return is to compensate for estate tax having been paid on the same money.
