In a large skillet, cook beef and onion in butter over medium heat until meat is no longer pink.
Stir in the mushrooms, flour, garlic, salt and pepper. Cook and stir for 5 minutes. Add chili sauce and Worcestershire sauce.
Reduce heat; cook, uncovered, for 10 minutes. Stir in sour cream just before serving; heat through (do not boil). Serve with noodles.