Cook pasta as directed on package, omitting salt.
Meanwhile, heat oil in large skillet on medium heat. Add vegetables and garlic; cook and stir 3 min. or until vegetables are crisp-tender. Stir in chicken, sauce and oregano; bring to boil, stirring frequently. Remove from heat.
Drain pasta. Add to sauce with Singles; stir. Top with mozzarella and Parmesan; cover. Let stand 5 min. or until mozzarella is melted.