Prepare outdoor grill with medium-hot coals, or heat gas grill to medium-hot, or heat oven broiler. Lightly coat grill rack or broiler-pan rack with nonstick cooking spray.
Sauté onion in oil in small non-stick skillet over medium-low heat until softened, about 10 minutes; do not let brown. Remove from heat.
Tear 1 hamburger bun into pieces and place in food processor. Whirl until fine crumbs form.
Mix together the ground chicken, egg, barbecue sauce, salt, pepper, crumbs and sautéed onion in medium-size bowl. Stir in corn kernels. Shape into 6 equal patties.
Grill or broil patties about 4 inches from heat, turning once, for 10 minutes or until instant-read thermometer inserted in centers registers 165°F. Serve on soft roll with sliced red onion and extra barbecue sauce.