In a large mixing bowl, combine the turkey, artichoke hearts, mayonnaise, sour cream, Parmesan cheese, mozzarella cheese, garlic powder, onion powder, salt, and pepper.
Transfer the mixture to a baking dish and spread it out evenly.
Bake in the preheated oven for 45 minutes, or until the top is golden and the casserole is heated through.
Let it cool for a few minutes before serving.
Notes:
This casserole is perfect for using up leftover turkey.