COOK macaroni until just tender, in accordance with package directions.
Meanwhile, in large, deep skillet set to medium (350° F), BROWN hamburger; DRAIN.
ADD onions, using a tablespoon of water to prevent sticking; BROWN.
ADD tomatoes and cooked macaroni, STIRRING lightly.
COVER; SIMMER for 10 minutes.
ADD cheese, RECOVER; let MELT; STIR in salt and pepper.
Per Serving (excluding unknown items): 976 Calories; 52g Fat (41.2% calories from fat); 53g Protein; 113g Carbohydrate; 4g Dietary Fiber; 151mg Cholesterol; 2404mg Sodium. Exchanges: 6 1/2 Grain(Starch); 4 1/2 Lean Meat; 2 Vegetable; 7 Fat.