Between CA & OR it's the nonresident return that takes the other state tax credit (a few other states are like that as well) contrary to the general rule. So, all you have to do is make sure that TT/CA computes at some point after you have completed TT/OR. TT/CA should be asking you for more information about the portion of total income in OR that is also being taxed by CA, and the OR tax on that amount.
