Cook the pasta in salted water according to package instructions to al dente. Drain and set aside the cooked pasta. To avoid the pasta from sticking together, mix in a little bit of oil, about 1 teaspoon into the pasta.
In a large mixing bowl, add the freshly grated cheeses and mix to combine. Transfer 12 ounces (3 cups) of the cheese mixture into a separate bowl. That will be for the sauce. The remaining cheese will be used for layering and topping the mac and cheese.
In a large saucepan or pot under medium heat, melt the butter. Mix in the seasonings (dried parsley, dried oregano, salt and black pepper) and then the flour. Cook the flour mixture while whisking continuously for 1 to 2 minutes.
Next, slowly whisk in the milk into the roux followed by the heavy cream. Cook the mixture while whisking continuously until it starts to thicken and can coat the back of a spoon, about 3 to 5 minutes or longer as needed.
Turn the heat down to low. Whisk in 12 ounces (3 cups) of the cheese mixture into the sauce until it is fully incorporated. Remove the pan from the heat.
In the pan with the sauce, add in the chicken and pasta. Mix ingredients together to combine making sure that all of the chicken and pasta are evenly coated in the cheese sauce.
Preheat the oven to 350F. In a large lightly greased 8 x 12 or 9 x 13 inch baking pan, spoon in half of the alfredo mac and cheese. Sprinkle over half of the remaining cheese mixture. Repeat this process ending with the last of the cheese mixture. Cover the pan with aluminum foil.
Transfer the assembled mac and cheese to the preheated oven and bake for 22 to 25 (for a more gooey consistency) or 25 to 30 minutes (for more set consistency). For a toasted top, remove the aluminum foil and broil the Mac and cheese for 3 to 5 minutes.
Let the Mac and Cheese rest at room temperature for 5 to 10 minutes. Top with finely chopped fresh parsley and freshly grated Parmesan cheese, optional. Serve Chicken Alfredo Mac and Cheese while warm. Enjoy!