Enter the 1099-Misc exactly as received. Do not change it. Turbotax (TT) will do that for your. After identifying the reason for the 1099-Misc as "prize", you will reach a screen called. "Fair market value of prizes and awards". There you will enter an adjustment for the prize value. In your case enter -17,100. TT will enter the 1099-Misc amount and the adjustment on line 21 of form 1040 (Schedule 1).
