TurboTax explains a nominee adjustment in this manner:
"Nominee Interest: Some or all of the interest belongs to someone else but the entire amount was reported under your Social Security number. This includes interest belonging to your child but reported under your ID number."
It's not unusual for a broker or fiduciary to send a form like a 1099-INT under one social security number when the interest, in part or all, belongs to someone else. A nominee adjustment removes the amount from your taxable income.
In Turbotax you do this by entering the 099-INT, then checking on the next screen that you need to adjust the amount. You'll then be able to enter the adjustment amount and check the reason for the adjustment.
You can do the same on a 1099-DIV.
