I worked in North Dakota and full-time student, but was a Minnesota resident. Does that mean I don't have to file in one of the states?

[DanielV01]

You are correct.  North Dakota and Minnesota are reciprocal states, which means if you live in one but work in the other, you only pay taxes where you live.  Thus, if no ND tax was taken out of your check (and it should not have,) you will only file a Minnesota resident return.  If ND did take out tax for ND, you would file a North Dakota nonresident reciprocal return to get all of your taxes back paid to ND (but then you have to pay tax on that income to MN).  Here is an FAQ that has more information for you:  https://ttlc.intuit.com/replies/4776822