Preheat your oven to 375°F (190°C) and lightly grease a 9x13 inch baking dish with non-stick cooking spray.
Bring a large pot of salted water to a boil and cook the fettuccine according to package directions until al dente, then drain thoroughly.
While the pasta cooks, add the cubed chicken to a large skillet over medium-high heat and cook for 6-8 minutes, stirring occasionally, until the chicken is cooked through and no longer pink in the center.
In the prepared baking dish, combine the drained hot pasta, cooked chicken, and both jars of Alfredo sauce, stirring until everything is evenly coated in the sauce.
Sprinkle the mozzarella cheese evenly over the top of the pasta mixture, followed by the grated Parmesan cheese.
Bake uncovered for 20-25 minutes, or until the cheese is completely melted and the edges of the sauce are bubbling gently.
Remove the bake from the oven and let it rest for 5 minutes before serving to allow the sauce to thicken slightly.
