Brown ground beef with peppers and onions until meat is brown and peppers begin to soften, drain. Return pepper mixture to sauce pan, stir in pasta sauce, oregano, one cup of mozzarella cheese and pasta. Pour a thin layer of pasta sauce into the bottom of a 9 x 13 pan and then spoon the pasta and peppers into the pan. Sprinkle the remaining cheese on top of the pasta. Bake uncovered for 30 minutes in a 375 degree oven until it is hot and bubbly.