Grill chicken 8 min. Meanwhile, cook and stir vegetables in hot oil in large skillet on medium heat 5 min. or until crisp-tender.
Remove from heat; cover to keep warm.
Turn chicken; brush with barbecue sauce. Grill 7 to 9 min. or until chicken is done (165F), turning and brushing occasionally with remaining sauce and adding rolls, cut sides down, to the grill for the last few minutes.