COOK pasta as directed on package, omitting salt. Meanwhile, cook and stir chicken, garlic and dressing in large skillet on medium heat 5 min. or until chicken is no longer pink. Stir in spaghetti sauce and spinach; cook 5 min. or until chicken is done, stirring occasionally.
DRAIN pasta. Add to sauce mixture; stir to evenly coat. Stir in 1/2 cup mozzarella. Sprinkle with remaining mozzarella and Parmesan cheese.