Boil salted water in a large pot and cook the fusilli until al dente, then drain and set aside.
Preheat your oven to 375°F and season the chicken pieces with salt and pepper.
Heat olive oil in a large skillet over medium heat.
Add the seasoned chicken and cook until browned and cooked through, about 6-8 minutes.
Remove the chicken from the skillet and set it aside.
In the same skillet, melt the butter, then add the minced garlic and cook for about 1 minute until fragrant.
Whisk in flour for 1 minute, then slowly pour in the milk and heavy cream while whisking continuously until smooth and thickened, about 3-4 minutes.
Stir in grated parmesan cheese, 1 cup of shredded mozzarella, and Italian seasoning until melted and creamy.
In a bowl, mix cooked fusilli, chicken, and creamy sauce until well combined.
Transfer the mixture to a greased 9x13 baking dish and top with the remaining shredded mozzarella cheese.
Bake in the preheated oven for 20-25 minutes or until bubbly and golden.
Let the dish rest for a few minutes before serving. Garnish with chopped parsley if desired.