This is my primary source of income and not a fellowship just for supplies/research.
I received income from a university also and entered that W2 already but don't know how to report the income from the NSF grant.
The way that you report income received through an NSF postdoc grant would depend on how they are reporting the grant they paid to you. They should issue a tax reporting document. If they do not, then you need to still report it correctly on your return.
Previously, it would have been reported on a 1099-MISC, however, since creation of the new 1099-NEC, that is probably how it would be reported on the TurboTax return.
Contact your Supervisor in the program and ask them if they will be issuing a tax reporting document.
Since the grant is your primary source of income, then you must determine if you are an employee, following instructions from others to do your job or if you manage your own work as you think it should be done. If you work on your own then this would be considered self-employment income since you are providing services and should be reported on Sch C as a sole proprietor.
Please refer to the following link for additional information: