Step 1: Preheat your oven to 350°F (175°C).
Step 2: In a large pot, bring salted water to a boil. Cook the jumbo pasta shells according to package instructions until al dente. Drain and set aside to cool slightly.
Step 3: In a mixing bowl, combine shredded chicken, ricotta cheese, mozzarella cheese, parmesan cheese, garlic powder, Italian seasoning, salt, and pepper. Mix until well incorporated and creamy.
Step 4: Take a generous amount of the filling and stuff each pasta shell. Place the filled shells in a greased baking dish, open side up.
Step 5: Pour the Alfredo sauce evenly over the stuffed shells, ensuring they are well covered.
Step 6: Cover the baking dish with foil and bake for about 25 minutes. Remove the foil and bake for an additional 10-15 minutes, until the top is golden and bubbling.
Step 7: Let it cool for a few minutes, then garnish with fresh chopped parsley before serving.