If your return does not include a Schedule C and you have entered income on Form 1099-NEC, then that is the problem that TurboTax is trying to get you to fix.
Income reported on Form 1099-NEC is not reportable directly on your tax return. Just entering the information on that form is only the first step. Since it is self-employment or 'non-employee compensation' it must be associated with a Schedule C, even if there are no expenses being claimed.
The information required for the Schedule C will include the type of business, the business name (or your name if there is no specific business name), the business address (or your address), etc.
Try going back to the section where you entered the Form 1099-NEC if you entered it on its own and delete that entry. Use these steps:
This will bring you to the summary of all Form 1099-NEC that you have entered. Click Delete or the trash can icon next to each one.
Next, you will re-enter the Form 1099-NEC as part of the Schedule C so that the income is reported directly as part of your Business Income and Expenses and within the correct form and section of your return.
Use these steps to go to the Schedule C section of your return.
If you already have a Schedule C in your return, edit it and go to the section to Add Income. This is where you will re-enter the Form 1099-NEC.
If you do not already have a Schedule C in your return, follow the prompts and enter the information about your work/business for which you received the Form 1099-NEC. Then continue through that section to Add Income and enter the Form 1099-NEC plus any other income you received for that self-employed business.
Don't forget you can also claim expenses related to your business.
After you are finished, the error condition should be eliminated.