Preheat the oven to 375°F. Grease a 9×13-inch baking dish and set aside.

Bring a large pot of salted water to a boil. Cook the pasta according to package instructions until al dente. Drain and set aside.

In a large skillet, heat olive oil over medium heat. Season the diced chicken with salt, pepper, and Italian seasoning. Cook the chicken until golden brown and fully cooked, about 5-7 minutes. Remove from heat and set aside.

In the same skillet, melt the butter over medium heat. Add the minced garlic and sauté for 1-2 minutes until fragrant. Sprinkle in the flour and whisk continuously for about a minute to create a roux.

Gradually pour in the heavy cream and milk, whisking constantly to prevent lumps. Bring the sauce to a simmer and cook until slightly thickened, about 3-4 minutes.

Stir in the Parmesan cheese, ½ cup mozzarella cheese, salt, black pepper, garlic powder, onion powder, and crushed red pepper flakes (if using). Mix until the cheese is fully melted and the sauce is smooth.

Add the cooked pasta and chicken to the sauce, stirring to coat everything evenly. Pour the mixture into the prepared baking dish.

Sprinkle the top with the remaining ½ cup mozzarella cheese, additional Parmesan cheese, and panko breadcrumbs (if using).

Bake for 20-25 minutes, or until the cheese is melted and bubbly. If a golden crust is desired, broil for an additional 2-3 minutes until lightly browned.

Remove from the oven and let the pasta bake sit for 5 minutes before serving. Garnish with chopped parsley and serve warm.