HEAT oven to 375ºF.
COOK pasta in large saucepan as directed on package, omitting salt and adding spinach to the boiling water for the last minute.
MEANWHILE, cook and stir chicken and basil in large nonstick skillet sprayed with cooking spray on medium-high heat 3 min. Stir in tomatoes and spaghetti sauce; bring to boil. Simmer on low heat 3 min. or until chicken is done, stirring occasionally. Stir in Neufchatel.
DRAIN pasta mixture; return to pan. Stir in chicken mixture and 1/2 cup mozzarella; pour into 2-qt. casserole sprayed with cooking spray.
BAKE 20 min. or until heated through; top with remaining cheeses. Bake 3 min. or until mozzarella is melted.