Preheat your oven to 425°F (220°C).

In a large mixing bowl, combine the shredded chicken, marinara sauce, mozzarella cheese, Parmesan cheese, dried oregano, garlic powder, Italian seasoning, salt, and pepper. Mix well until all ingredients are evenly combined.

Roll out the pizza dough on a floured surface to a thickness of about ¼ inch. Cut the dough into circles, approximately 6-8 inches in diameter.

Place a generous scoop of the chicken mixture on one half of each dough circle, leaving a border around the edge.

Fold the other half of the dough over the filling to create a half-moon shape. Press the edges together firmly to seal, and use a fork to crimp the edges for a decorative touch.

Transfer the calzones to a baking sheet lined with parchment paper. Brush the tops lightly with olive oil to promote browning.

Bake in the preheated oven for 15-20 minutes, or until the calzones are golden brown and puffed.

Remove from the oven and let cool for a few minutes. Serve warm, garnished with fresh basil if desired.