POUR 1/4 cup barbecue sauce over chicken in shallow dish; turn chicken over to coat both sides of each breast. Refrigerate 1 hour to marinate.
HEAT barbecue to medium heat. Remove chicken from marinade; discard marinade.
GRILL chicken 5 to 7 min. on each side or until done (170ºF), brushing occasionally with remaining barbecue sauce the last few minutes.