What is the minimum time required to become a "resident" of the state?
When is a nonresident of North Dakota required to file a North Dakota individual income tax return?
https://www.nd.gov/tax/faqs/topics/4/A nonresident of North Dakota is required to file a North Dakota individual income tax return if the individual (1) is required to file a federal individual income tax for the tax year and (2) has any gross income from North Dakota sources.
"Gross income from North Dakota sources" includes
compensation for services performed in North Dakota, such as wages, salaries, tips, commissions, and fees; income from tangible property in North Dakota, such as rents, oil and gas royalties, and gain from the sale or exchange of the property; income from a trade or business carried on in North Dakota, whether as a sole proprietorship, partnership, or S corporation; income from an estate or trust, but only to the extent the income is derived from tangible property or a trade or business in North Dakota; income from gambling activity carried on in North Dakota; and unemployment compensation attributable to previous employment in North Dakota.
Gross income from North Dakota sources does not include the following items that are received while a nonresident of North Dakota; military pay, pensions, annuities, exempted under federal military and interstate commerce laws, and compensation exempted under federal military and interstate commerce laws, and compensation exempted under North Dakota's mobile workforce exemption law. Interest, dividends, and gains from the sale or exchange of intangible property are generally not included in gross income from North Dakota sources if received while a nonresident of North Dakota; however, they are included in gross income from North Dakota sources if they are derived from a trade or business that is carried on in North Dakota.