I am new at this, I didn't see this on here already, sorry if it is. It is dang good and easy!
PLACE large sheet of heavy-duty foil over half of grill grate; heat grill to medium heat. Meanwhile, place chicken in resealable plastic bag. Add 2 Tbsp. dressing; seal bag. Turn bag over several times to evenly coat chicken with dressing. Refrigerate 10 min. Remove chicken from bag; discard bag and dressing.
GRILL chicken on uncovered side of grill 6 min. Meanwhile, combine remaining dressing, tomatoes, cheese and basil.
TURN chicken over; place, cooked-side up, on foil on grill. Top with tomato mixture. Close lid. Grill 8 min. or until chicken is done (165ºF).