It depends. If your income from ND consisted solely of W-2 wages, you do not have to file an ND return. You would only file a return in your home state of MN. That's because the two states have tax reciprocity with regard to W-2 wages. Your income would be 100% taxable in MN.
But if you had income from ND other than W-2 wages, you'd have to file in both states.
If you qualify for reciprocity, you should submit ND Form NDW-R to your employer. Here's a link to that form: https://www.nd.gov/tax/data/upfiles/media/ndwrfillable.pdf?20190123091226
**Answers are correct to the best of my ability but do not constitute tax or legal advice.