I received a stipend that is federally taxable, but not state taxable. I can't figure out where to enter it so that I don't accidentally pay the state tax?

What form was it reported on? W-2? 1099-MISC? 1099-NEC?

 

Just enter it in the appropriate place for that form.

 

Once you get into the state interview, I expect that you will have the opportunity to exclude the income from state there.***

 

***Of course, this depends on the state, the type of form, and a dozen other things.

It was not reported on any of these forms, I need to self report it. I cannot find a way to exclude it from the NJ taxes when I report it federally as miscellaneous income.