Taco Casserole

1 box macaroni & cheese dinner
1 lb ground beef
1 pkg taco seasoning mix
3/4 c water
3/4 c sour cream
1 1/2 c shredded cheddar cheese
1 c thick 'n chunky salsa
1/2 c coarsely crushed tortilla chips

Preheat oven to 400 degrees. Prepare macaroni as directed on package. Brown meat and drain. Add taco seasoning  mix and water to meat; simmer 5 minutes. Stir sour cream into prepared macaroni & cheese. Spoon half of macaroni mixture into an 8-inch square baking dish; layer on  meat mixture, 1 cup cheddar cheese, and then remaining macaroni mixture. Cover and bake in oven for 15 minutes at 400 degrees. Top with tortilla chips, salsa and remaining 1/2 cup cheese. Bake, uncovered for 5 minutes or until cheese is melted. Makes 6 servings of 1 cup each.