1Heat oven to 350°F. In 10-inch skillet, cook beef over medium heat 8 to 10 minutes, stirring occasionally, until thoroughly cooked; drain. Stir in 1/2 cup onion, 1/2 cup sour cream, 1 cup cheese, the cilantro and pepper. Cover; remove from heat.
2In 2-quart saucepan, heat bell pepper, water, chili powder, oregano, cumin, chiles, garlic and tomato sauce to boiling, stirring occasionally; reduce heat. Simmer uncovered 5 minutes. Pour into ungreased 9-inch glass pie plate.
3Dip each tortilla into sauce in pie plate to coat both sides. Spoon about 1/4 cup beef mixture down center of each tortilla; roll up. Place, seam side down, in ungreased 11x7-inch (2-quart) glass baking dish. Pour remaining sauce over enchiladas.
4Bake uncovered about 20 minutes or until bubbly. Garnish with additional cheese, sour cream and chopped onion.