Preheat oven to 375 degrees F.
Lightly spray a 9×13-inch baking dish with cooking spray. Set aside.
Bring a large pot of water to boil and cook pasta shells according to package directions aiming for al dente.
Drain and set aside. For them not to stick, gently toss them with some olive oil.
In the meantime, in a large bowl combine chicken, ricotta cheese, cream cheese, sour cream, parmesan, 1 cup of mozzarella cheese, and basil, parsley.
Stir in chopped spinach.
Add the mixture to a piping bag.
Stuff pasta shells with the cheese mixture and arrange them in the prepared baking dish.
Spread Alfredo sauce on top and top with remaining mozzarella cheese.
Bake uncovered for 30 to 35 minutes.