Preheat the oven to 350°F (175°C) and lightly spray a 9-inch pie plate with cooking spray; set aside.
Cook 8 oz spaghetti according to package directions until al dente, drain well, and return to a large bowl.
While pasta is warm, toss it with 2 eggs and 4 tablespoons of the Parmesan until evenly coated.
Press the spaghetti mixture firmly into the bottom and up the sides of the prepared pie plate to form a crust.
In a bowl, combine 2 1/2 cups chopped cooked chicken, the 10 oz Alfredo sauce, and 1/4 cup shredded mozzarella; stir until mixed.
Spread the chicken-Alfredo filling evenly into the spaghetti crust.
Sprinkle the remaining 1 1/4 cups shredded mozzarella and the remaining Parmesan over the top.
Bake for 30 to 40 minutes, until the filling is heated through and cheese is melted and bubbly.
Let the pie stand for 10 minutes before slicing and serving to allow it to set.
