COOK rice as directed on package.
MEANWHILE, heat large nonstick skillet sprayed with cooking spray on medium heat. Add chicken, onions and oregano; cook 6 min. or until chicken is lightly browned on both sides and onions are crisp-tender, turning chicken after 3 min. Add tomatoes, dressing and garlic; stir gently. Cook 4 to 6 min. or until chicken is done (165ºF), turning chicken after 3 min. Stir in olives.
SPOON rice onto platter; top with chicken and sauce.