HEAT 2 Tbsp. dressing in large nonstick skillet on high heat. Add chicken; cook 5 min. or until done, stirring occasionally. Remove chicken from skillet; cover to keep warm.
ADD remaining dressing, onions and peppers to skillet; cook and stir 4 to 5 min. or until vegetables are crisp-tender. Add chicken and tomatoes; cook and stir 3 to 4 min. or until heated through.
TOP with cheese.