If you were a non-US resident for 2020, the only reason to file a tax return is if you had income from a US source in 2020. US-source income includes working temporarily in the US or selling real estate in the US, but it generally does not include working outside the US for a US-based company.
If you are a non-resident and required to file a US tax return, you need to file a 1040-NR for 2020. Turbotax does not support non-resident returns so you will have to find another company.
If you are not required to file a US return under the tax law, then you don't have to (and can't) file a US tax return just for FAFSA. Read the instructions carefully per @rjs . For FAFSA, they want to know your total income, so they can determine if you need financial aid. If you had foreign income and filed a foreign tax return, use that information, not a zero dollar US return that hides your overseas income.
