For others, I'll add what I found (being really new to all this) when I went to the state sites. The key is to search "nonresident" on each state's site. If that doesn't help, try googling this with your desired state name, e.g.:
"who must file nonresident return michigan"
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NY nonresident page: wow, this seems unlimited - any amount.
"You must file Form IT-203, Nonresident and Part-Year Resident Income Tax Return, if you:
- were not a resident of New York State and received income during the tax year from New York State sources, or
- moved into or out of New York State during the tax year."
Note, the linked form page says "We've partnered with the Free File Alliance again to offer you more options to e-file your New York State income tax return—at no cost!" so it may not be necessary to buy the NY return from TT.
It's a fillable PDF. Requires info from completed 1040.
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Michigan says to file if "You had income earned in Michigan and/or attributable to Michigan." But they don't say what "attributable to" means. @ColeenD3 does it mean "paid by someone located in MI"? I had one $4000 payment from a Michigan non-profit.
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That's all for tonight... grateful for this forum and I hope this helps another
