According to the Nebraska website:
A Resident of Nebraska is an individual that is domiciled in the state. If the individual is not domiciled in the state but maintains a place of abode within the state and is present for 183 days or more, they will be considered a resident.
A Nonresident of Nebraska is an individual that is not a resident of Nebraska, but has received income which is subject to taxation by the state of Nebraska.
A Part-Year Resident is an individual that moved into or out of Nebraska. Therefore, the individual is a resident for only a part of the year.
If one spouse is a resident and the other is not, you can choose to file as either married filing joint (all income is taxed on resident return) or married filing separate (only resident spouse is taxed as resident) on the Nebraska return. To file separate returns within your account, you can file the federal return and wait for the return to be accepted. Then, change the filing status for the primary taxpayer and file a separate return for the first spouse. The second spouse will need to create a new account and file the separate state return in that account (if required to file).
For more information, see: