Cook the jumbo pasta shells according to the package instructions until al dente. Drain and set aside to cool slightly.
In a large mixing bowl, combine the shredded chicken, ricotta cheese, half of the mozzarella cheese, Parmesan cheese, garlic powder, Italian seasoning, salt, and pepper. Mix until well combined.
Fill each cooked jumbo shell with the chicken and cheese mixture. Place the stuffed shells in a baking dish, opening side up.
Pour the Alfredo sauce evenly over the filled shells, ensuring they are fully covered.
Sprinkle the remaining mozzarella cheese over the top of the shells.
Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes.
Remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and golden.
Once done, remove from the oven and let it cool for a few minutes before serving.
Garnish with fresh chopped parsley before serving.