Mix cola and barbecue sauce until blended. Pour 1 cup cola mixture over chicken in medium bowl; toss to evenly coat chicken with cola mixture.
Refrigerate 1 hour to marinate.
Heat grill to medium-low heat. Remove chicken from marinade; discard marinade. Reserve 1-1/4 cups of the remaining cola mixture for serving with the cooked chicken. Grill chicken 30 min. or until done (165°F), turning and brushing occasionally with remaining cola mixture.
Serve chicken topped with the reserved cola mixture.