Combine mozzarella and 1/4 cup Parmesan. Cut 3 Singles in half. Cook pasta in large pot as directed on package.
Meanwhile, cook chicken in large nonstick skillet 5 min. on each side or until done (165ºF). Top each breast with 1 Tbsp. pasta sauce, about 1-1/2 Tbsp. of the mozzarella mixture and 1 Singles piece; cover skillet. Remove from heat. Let stand 3 to 5 min. or until cheese is melted.
Drain pasta; return to pot. Stir in remaining pasta sauce and Singles; cook and stir 3 min. or until sauce is heated through and Singles are melted. Spoon onto platter; top with chicken, remaining Parmesan and parsley.