Spray 3 1/2 - to 4-quart slow cooker with cooking spray. In large bowl, toss burger crumbles and flour until coated. Stir in tomatoes, peas and carrots and dried minced onion. Spoon into slow cooker.
Microwave potatoes as directed on package; stir. Spread over vegetable mixture in slow cooker.
Cover; cook on Low heat setting 4 hours. Increase heat setting to High. Sprinkle cheese over potatoes. Cover; cook 7 minutes longer or until cheese is melted. Garnish with chives.