In 3 1/2 to 4-quart slow cooker, combine beef, carrots, onion and bell pepper. Add flour, paprika, salt, thyme and pepper; toss beef and vegetables to coat. Add chili sauce and broth; mix well.
Cover; cook on low setting for 7 to 8 hours or until beef is tender.
Add mushrooms; mix well. Cover; cook an additional 20 to 30 minutes or until mushrooms are tender.
Meanwhile, cook noodles to desired doneness as directed on package. Drain.
Stir sour cream into stew until well mixed. To serve, spoon noodles into shallow bowls. Top with stew; sprinkle with parsley.