How do I enter non-qualified 529 withdrawal due to AOTC? I cannot override Schedule 1 line 8 to enter, and don't know which line in line 8 to use.

To enter an amount on Line 8, follow the path below:
 

• Personal Taxes/Federal Taxes -  depending on what version you are using  >>
• Personal Income/Wages & Income  >>
• Less Common Income - last section  >>
• Miscellaneous Income 1099-A, 1099-C  - last section in the list  >>
• Other Reportable Income - last item in miscellaneous
• Enter a description and amount - amounts reported here go to Schedule 1, Line 8 and then flow to Form 1040, line 8.

Earnings on 529 plans aren’t taxed by the federal government nor most states, as long as the distributions (Form 1099-Q) are used toward qualified education expenses.    If all the 1099-Q was used for room and board, it is not taxable, and you don't have to enter the 1099-Q.    You can delete it off her return.

You only need to enter it IF any of the distributed amounts were not used on qualified educational expenses.   IF the 1099-Q has to be reported (it wasn't used for QEE), it goes on the return of whoever's social security number is on the form.   If the distribution exceeds these expenses, then you must report the earnings on the excess as other income-Line 8 on your tax return.   Use the instructions above to report 'other income'.  When you pay a student’s school expenses with these funds, you cannot claim a tuition deduction or either of the educational tax credits for the same expense.  

Beneficiary's Tax Implications