To apply a portion of your state refund to next years taxes look for the section that deals with calculating estimated payments for 2016. Even if you don't need TurboTax to calculate the ES payments, the option to apply your refund will be within those screens. Each state return is set up a little differently in TurboTax and navigating directly to the section you need varies.
For Oregon, go through the tax return until you come to the page "Your 2016 Oregon taxes are ready for us to check" click Edit next to Other Situations. You will then be brought to a page titled, "A few things before we wrap up your state taxes" under Other Situations click start next to Apply Overpayment to Next Year.
