Fill a large pot with water and bring to boil. Add manicotti pasta and cook based on package instructions. When done, drain and set pasta on a dish lined with wax paper (See Note 1) to cool. Do not overlap pasta on top of each other.
Grease a 9' x 13' baking dish, then layer with a thin layer of Alfredo sauce.
Pre-heat oven to 375℉.
In a large bowl, combine chicken, spinach, ricotta cheese, 1 cup mozzarella cheese (set 1/2 cup aside as topping), parmesan cheese, garlic, oregano, and basil. Mix to combine.
Stuff manicotti pasta with chicken and spinach mixture (see Note 2), then place on baking dish layered with Alfredo sauce.(See Note 3)
Smother the top of the manicotti with more Alfredo sauce, then top with 1/2 cup of mozzarella cheese.
Bake manicotti in the oven for 25-30 minutes.
Remove from oven and let manicotti rest for 5 minutes before garnishing it with parsley and serving. Enjoy!