COOK spaghetti as directed on package, omitting salt. Meanwhile, brown meat in medium skillet; drain. Stir in spaghetti sauce; cook on medium-low heat 5 min. or until heated through, stirring frequently.
DRAIN spaghetti. Add to meat sauce; mix well. Combine next 4 ingredients.
FILL taco shells with mozzarella and spaghetti mixture; sprinkle with Parmesan. Serve topped with lettuce salad.