Lay the pizza crusts flat on a long sheet of aluminum foil. Drizzle each crust with some olive oil.
Using a spoon, cover each crust with a thin layer of pasta sauce. Then add the cooked chicken, dividing the chicken equally between each crust.
Sprinkle the mozzarella and parmesan cheese on the pizzas. Finally, add garlic and a pinch of oregano to each pizza.
Place the whole sheet of aluminum foil with the pizzas on it on the grill. Grill on medium for about 5 minutes with the cover down until the cheese is melted and bubbly.
Serve hot.