SPRAY large skillet with cooking spray. Add chicken; cook and stir 5 min. on medium-high heat. Add green pepper and onion; cook 5 min. or until chicken is cooked through and vegetables are tender.

STIR in tomatoes, water and Macaroni. Bring to boil. Reduce heat to low; cover.

SIMMER 10 min. or until Macaroni is tender, stirring twice. Stir in Cheese Sauce Mix until blended.