Prepare the pizza dough according to your favorite recipe or thaw store-bought dough completely.
Preheat the oven to 475°F (246°C) for at least 15–20 minutes. If using a pizza stone, place it in the oven while it preheats.
Lightly grease a pizza pan or baking sheet with half of the olive oil and sprinkle with cornmeal.
Punch down the dough and shape it into a 12-inch circle on a lightly floured surface. Form a slightly raised edge around the crust.
Transfer the dough to the prepared pan and let it rest for a few minutes.
Press small dimples across the dough with your fingertips to reduce bubbling.
Brush the remaining olive oil over the surface.
Spread 1/3 cup barbecue sauce evenly across the dough.
Toss the cooked chicken with the remaining barbecue sauce.
Evenly distribute the chicken over the pizza.
Sprinkle mozzarella and smoked Gouda over the top.
Add the sliced red onion.
Bake the Homemade BBQ Chicken Pizza for 14–15 minutes, or until the crust is golden brown and the cheese is bubbly.
Remove from the oven and garnish with chopped cilantro or basil.
Slice and serve immediately.