To prepare filling, heat a large nonstick skillet over medium-high heat. Coat pan with cooking spray. Add onion, bell pepper, garlic, and turkey; cook 5 minutes or until turkey loses its pink color. Add chili powder, oregano, 1/2 teaspoon salt, tomatoes, and beans; cook 3 minutes. Spoon turkey mixture into an 11 x 7-inch baking dish coated with cooking spray.