Chili Pasta Casserole

1 pound lean ground beef
1 medium onion, chopped
1/4 teaspoon salt
1/8 teaspoon black pepper
1 (15 ounce) can vegetarian chili with beans
1 (14 1/2 ounce) can Italian style stewed tomatoes, undrained
1 1/2 cups shredded sharp Cheddar cheese, divided
1/2 cup reduced fat sour cream
1 1/2 teaspoons chili powder
1/4 teaspoon garlic powder
8 ounces cooked pasta

Cook ground beef and onion in large skillet. Sprinkle with salt and pepper. Brown beef until no longer pink. Drain fat. Stir in chili, tomatoes with juice, 1 cup Cheddar cheese, sour cream, chili powder and garlic powder.

Add chili mixture to pasta and stir until pasta is coated. Sprinkle with remaining 1/2 cup cheese. Cover and cook 30 minutes until hot and bubbly.