Sold primary house in NE, then moved to OK in 2018. Entered 1099S in Turbotax and it wants us to fill out a 561NR for OK. Not sure how to fix.

You need to indicate that you are a part year resident for each state so that the income is allocated properly. Please see the screen shot below. 

If you were a resident of 2 different states during the tax year (for example, if you moved from one state to another), you'll normally file part-year returns in both states, assuming each state collects income tax and you had income in each state.

TurboTax handles part-year returns, but you need to make sure you've set up your personal information correctly to trigger the part-year state interviews:

1. With your return open, select Personal Info.
2. Click Edit next to your name.
3. Select your resident state from the State of Residence drop-down.
4. Answer Yes at the line below (that you lived in another state during 2018).
5. Select your former state from the Previous state of residence drop-down.

1. Enter the date you became a resident of your new state. This can be the date you arrived in that state.
2. Select Continue to return to the Your Personal Info Summary screen.

1. Repeat Steps 3-5 for your spouse, if needed.

After you finish your federal return, you'll automatically move to State Taxes, where you'll see your part-year states listed. We suggest you prepare the return for the state you currently live in, followed by your former state. 

Important: If you also see a nonresident state return on the State Taxes tab, complete that return before you work on your part-year return(s) to ensure your tax credits are calculated correctly.