Cook pasta shells al dente and set aside.
Combine chicken, cheeses, sour cream, and parsley in a bowl.
Fill each shell with the creamy chicken mixture.
Arrange shells in a baking dish, cover with Alfredo sauce, and top with mozzarella.
Bake at 375°F for 30–35 minutes until golden and bubbly.
Rest briefly, garnish with parsley, and enjoy!
