In a large skillet cook ground beef over medium heat until brown. Drain off fat.
In a 3-1/2- or 4-quart slow cooker combine meat, frozen potatoes, tomato sauce, and undrained tomatoes.
Cover and cook on low-heat setting for 6 to 8 hours or on high-heat setting for 3 to 4 hours. Remove liner from cooker or turn off cooker. Sprinkle meat mixture with cheese. Let stand 5 minutes or until cheese melts. Makes 4 servings.