Preheat the oven to 375°F (190°C).
Prepare the pasta according to the package directions until it reaches an al dente texture. Drain thoroughly and set aside.
Warm olive oil in a large skillet over medium heat. Add the minced garlic and cook until it releases a fragrant aroma, about 1 minute.
Incorporate the fresh spinach into the skillet, cooking until the leaves wilt.
In a spacious mixing bowl, combine the drained pasta, shredded chicken, wilted spinach, ricotta cheese, 1/2 cup of the mozzarella cheese, milk, salt, pepper, and dried oregano. Stir until the ingredients are evenly distributed.
Grease a 9x13 inch baking dish and transfer the mixture into it, spreading it out evenly.
Evenly sprinkle the remaining 1/2 cup of mozzarella cheese and grated Parmesan over the top.
Place in the oven and bake for 25-30 minutes, or until the surface is golden and bubbling.
Allow the dish to cool for a few minutes before serving to enhance flavor and texture.