1Heat oven to 350°F. In 10-inch skillet, cook beef and onion, stirring occasionally, until beef is thoroughly cooked; drain. Stir in both pouches enchilada sauce (from dinner kit), the seasoning mix (from dinner kit), water and chiles; heat until hot.
2In ungreased 11x7-inch baking dish, spread 1 cup of the beef mixture. Cut tortillas (from dinner kit) in half. Place 6 tortilla halves on beef; spread with 1/2 cup of the sour cream. Top with 1/2 cup of the cheese, 1 cup of the beef mixture and remaining 6 tortilla halves. Top with remaining sour cream, remaining beef mixture and remaining cheese.
3Bake 30 minutes. If desired, serve with additional sour cream, diced red bell pepper and chopped fresh cilantro.