Preheat oven to 415°F. Stir together tomato sauce, pinto beans, black beans, red kidney beans and seasoning until combined.
Stir together ricotta, 1 cup mozzarella and 1/2 cup parmesan.
Layer one third of sweet potato rounds into bottom of greased 9 x 13-inch baking dish. Spread one third of bean mixture over top. Spread half the cheese mixture over beans. Repeat layers twice. For final cheese layer, use reserved mozzarella and parmesan (no ricotta on top layer).
Cover with foil and bake for 30 minutes. Remove foil and bake uncovered for 10 to 15 minutes or until golden brown and bubbly.
Sprinkle with parsley or basil before serving.