Preheat your oven to 350°F (175°C). Gather all your ingredients together.

Cook the manicotti shells according to package instructions until al dente, about 8–10 minutes. Drain and rinse under cold water.

In a skillet over medium heat, cook diced chicken for about 5-7 minutes until no longer pink. Season with salt and pepper.

In a mixing bowl, combine the cooked chicken, ricotta, mozzarella, Parmesan, parsley, salt, and pepper. Mix well.

Fill each manicotti shell with the chicken and cheese mixture using a spoon or piping bag.

In a saucepan, melt butter then add garlic. Pour in cream and bring to a simmer. Stir in more Parmesan until thickened, about 3-5 minutes.

Spread a thin layer of Alfredo sauce in a baking dish. Place filled manicotti shells in single layer and cover with remaining sauce.

Cover with foil and bake for 30 minutes. Remove foil and bake for an additional 10-15 minutes until bubbly and golden.

Let it rest for about 5 minutes before serving. Garnish with fresh parsley.