In each of two greased 13x9 inches baking dishes, arrange 6 tortillas. Top with 1 cup chicken, 2/3 cup kidney beans, 1 cup salsa, 1/2 cup green pepper, about 1/3 Jack cheese, and 1/2 cup Cheddar cheese. Repeat layers twice.
Cover and bake at 350 degrees for 25 minutes. Uncover, bake 10-15 minutes longer or until the cheese melts. Let stand 10 minutes before serving.