HEAT large nonstick skillet sprayed with cooking spray on medium-high heat. Add chicken; cover skillet with lid. Cook 5 to 7 min. on each side or until chicken is cooked through (170ºF). Remove chicken from skillet; keep warm.
REDUCE heat to medium. Add cream cheese spread, water, pesto and tomatoes to skillet. Cook, uncovered, 2 min. or until heated through, stirring occasionally.
RETURN chicken to skillet. Cook and stir 1 min. or until chicken is coated and heated through. Sprinkle with shredded cheese.