Preheat oven to 375˚F. Cook pasta in a large pot of salted water until al dente according to package instructions then drain hot water and add cold water to the pot to stop the cooking process and prevent noodles from sticking together. Shred 4 cups of chicken.
Place a pot or large saucepan over medium heat, add 1 tablespoon olive oil and saute onions and garlic for 3-4 minutes or until softened. Add 4 tablespoon butter and whisk in ⅓ cup flour. Continue whisking 3 minutes or until flour mixture is golden.
Add 2 ½ cups chicken broth, 1 ½ cups heavy cream, 4 oz softened cream cheese, 2 teaspoon salt, and ½ teaspoon black pepper. Whisk until smooth and simmer 5 minutes until thickened to a light gravy consistency.
Add thawed and drained chopped spinach, and stir to combine then remove from heat.
In a large bowl, whisk together: ricotta, egg, ¼ cup parmesan, and ¼ cup parsley.
Add a little bechamel sauce on the bottom of a 9x13 casserole dish, add 3 noodles, Add ½ ricotta sauce, ½ shredded chicken, ¾ cup mozzarella, ¾ cup provolone, then ladle on ⅓ of spinach sauce.
Add 3-4 noodles, Add ½ ricotta sauce, ½ shredded chicken, ¾ cup mozzarella, ¾ cup provolone, then ladle on ⅓ of spinach sauce.
Add 3-4 noodles, remaining ⅓ sauce, and sprinkle on ½ cup mozzarella and ½ cup provolone.
Cover and Bake: Cover with a large sheet of foil. Bake on the center rack in a preheated oven at 375˚F for 40 minutes then uncover and bake for an additional 10 minutes to brown the cheese. Rest at least 20 minutes uncovered before slicing.