Preheat the oven to 375°F (190°C).
In a large mixing bowl, combine the shredded chicken, marinara sauce, ricotta cheese, garlic powder, Italian seasoning, salt, and black pepper. Mix until well combined.
Spread the chicken mixture evenly in a greased 9x13-inch baking dish.
In a separate bowl, mix the almond flour with half of the mozzarella cheese and half of the Parmesan cheese. Sprinkle this mixture evenly over the chicken layer.
Top with the remaining mozzarella and Parmesan cheese.
Bake in the preheated oven for 25-30 minutes, or until the cheese is bubbly and golden brown.
Remove from the oven and let it cool for 5 minutes. Garnish with fresh basil if desired before serving.