Step 1: Cook the Pasta
Boil the jumbo shells in salted water until al dente.
Drain and set aside to cool.
Step 2: Make the Filling
In a large bowl, mix together shredded chicken, ricotta cheese, mozzarella, Parmesan, egg, garlic powder, Italian seasoning, salt, and pepper.
Stir until creamy and well combined.
Step 3: Prepare the Alfredo Sauce
Melt butter in a large skillet over medium heat.
Sauté the minced garlic for about 1 minute.
Pour in heavy cream and simmer for 3-4 minutes.
Add Parmesan cheese, black pepper, and nutmeg. Stir until creamy and smooth.
Step 4: Assemble the Dish
Preheat oven to 375°F (190°C).
Pour 1 cup of Alfredo sauce into the bottom of a 9x13 baking dish.
Fill each pasta shell with 2-3 tablespoons of the chicken mixture and place in the dish.
Pour the remaining Alfredo sauce over the shells.
Top with extra mozzarella and Parmesan cheese.
Step 5: Bake
Cover with foil and bake for 20 minutes.
Remove foil and bake for an additional 5-7 minutes until cheese is melted and bubbly.