Preheat oven to 350°F. Cook pasta according to package instructions until almost al dente ( I cook mine about 1 minute less than directed for al dente).
While pasta is cooking, combine the sour cream and softened cream cheese in a medium mixing bowl and use an electric beater to mix until smooth and creamy. Add in the heavy cream and mix. Finally, mix in the milk.
From there, add in chicken, spinach, artichokes, 1 cup mozzarella cheese, parmesan, onion, garlic and seasonings. Stir to combine. When the pasta is cooked, drain it and then add it to an oil sprayed 9×13 inch pan.
Pour the spinach and artichoke mixture over the pasta and stir to combine and fully coat the pasta. Top with remaining mozzarella cheese and bake about 25 minutes, checking at 20 minutes, or until cheese on top is melted and mixture is bubbling. You can broil the last 2 minutes if desired for browned crispy cheese.
Cool for about 5-10 minutes before serving. Refrigerate leftovers.