1 (16 ounce) package spaghetti
2 pounds ground beef 1/4 cup chopped onion
2 (26.5 ounce) cans meatless spaghetti sauce
1 (16 ounce) container fat-free sour cream
2 cups shredded mozzarella cheese, divided
1/2 cup Parmesan cheese salt and black pepper to taste