Preheat the Oven: Preheat your oven to 350°F (175°C).

Cook the Pasta Shells: In a large pot, bring salted water to a boil. Cook the pasta shells until al dente according to package instructions. Drain and set aside.

Prepare the Filling: In a large mixing bowl, combine shredded chicken, ricotta cheese, cream cheese, mozzarella cheese, onion powder, Italian seasoning, and minced garlic. Season with salt and pepper to taste. Mix until well combined.

Fill the Shells: Carefully fill each cooked shell with the chicken and cheese mixture using a spoon.

Prepare the Sauce: In a saucepan over medium heat, pour in heavy cream and add parmesan cheese. Stir continuously until the cheese is melted and the sauce is smooth. Season with salt and pepper to taste.

Assemble the Dish: Spread a thin layer of cream sauce in the bottom of a baking dish. Arrange the filled shells on top of the sauce. Pour the remaining cream sauce over the stuffed shells.

Bake: Cover the dish with aluminum foil and bake in the preheated oven for 25 minutes. Remove the foil and bake for an additional 10 minutes, or until the tops are golden and bubbly.

Garnish: Remove from the oven and let it cool slightly. Sprinkle chopped fresh parsley over the top for garnish before serving.