I reside in WI. I worked in TN for 6 months. TN is a non income tax state. I used turbo tax for my federal return. When turbo tax transferred my income to WI state return, it transferred the total amount. Do I owe income tax to WI for the TN income? Or, should I fill out a WI return separately, reporting only WI income?

If you were a WI resident all year, then indeed you owe WI taxes based on all income for the year. An alternative would be if you could show that you were a TN resident for those 6 months - in that case you'd be filing a part-year resident return with WI and pay taxes only on income earned while a resident. However, I suspect that WI would look dimly on this - they could come after you to make you prove you were NOT a WI resident during those 6 months. It all comes down to whether your intent was to move to TN, and to prove that it would help to show that you rented an apartment or bought a home in TN, surrendered your WI drivers license for a Tennessee one, registered to vote iin TN, etc.