Combine 1/4 cup barbecue sauce and chicken in a bowl. Toss well; set aside.
Prepare grill. Place 1 crust on grill rack coated with cooking spray; grill 3 minutes or until puffy and golden. Turn crust, grill-mark side up; spread with 3 tablespoons barbecue sauce. Top with half of Gouda, chicken mixture, mozzarella, and green onions. Cover; grill 3 to 4 minutes or until cheese melts and crust is lightly browned. Sprinkle with half of cilantro. Repeat with remaining crust and toppings.