Pre-heat oven to 350°F.
Grease an 8 x 8-inch baking dish or a 9 x 13-inch baking dish with cooking spray.
Cook shells per package directions.
Place in cold water to stop cooking; drain and set aside.
In a medium bowl, add mozzarella, Parmesan and Romano cheese; mix to combine.
Set aside 1/2 cup of the mixture.
To the bowl of cheese, add cottage cheese, beaten egg, pepper, salt and shredded chicken; stir until fully combined.
Pour 1 cup of garlic Alfredo sauce into the bottom of your baking dish.
Stuff shells with chicken mixture and place in baking dish.
Cover with remaining Alfredo sauce and the cheese previously set aside.
Bake for 20 to 25 minutes, or until cheese is bubbly and lightly browned.
Remove from oven and allow to cool for 5 minutes.
Garnish with chopped parsley, if desired, and serve.
