It works like this:
Your home state can tax ALL of your income, regardless of where you earned it.
Other states (that have an income tax) can tax you as a non-resident on income you earned by actually working within that state. It doesn't matter if that income is reported to you on a W-2 or a 1099-MISC.
When you're taxed by both a non-resident state and your home state, you'll be able to take a credit on your home state return for taxes paid to the non-resident state. So you won't be double-taxed.
In many (but not all) states, a non-resident has to file a tax return only if their income in that state exceeds a certain filing threshold. Some states requiring filing by anyone who had to file a federal return. You can find a state's non-resident filing requirements on its tax website.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
