Preheat the grill to medium-high heat.
In a large bowl, combine the chicken breasts and barbecue sauce. Toss to coat the chicken evenly.
In another bowl, mix the chopped bell peppers, zucchini, and red onion with olive oil, garlic powder, onion powder, salt, and pepper.
Lay out the aluminum foil sheets on a flat surface. Place a portion of the vegetable mixture in the center of each sheet, followed by a chicken breast on top.
Fold the sides of the foil over the chicken and vegetables, then roll up the ends to seal the packets tightly.
Place the foil packets on the grill and cook for 20-25 minutes, or until the chicken is cooked through and the vegetables are tender.
Carefully remove the packets from the grill and let them sit for a few minutes before opening, as steam will escape.