Preheat oven to 350℉ and grease a 9x13-inch baking dish; set aside.
Boil the lasagna noodles as instructed on the box. Drain the water and set the noodles aside.
9 lasagna noodles
In a large bowl, combine the ricotta cheese, diced chicken, chopped spinach, egg, Italian seasoning and 3 cups of the mozzarella cheese.
3 cups ricotta cheese, 3 cups diced chicken, 1 1/2 cups chopped fresh spinach, 1 egg, 1/2 teaspoon Italian seasoning, 4 cups shredded mozzarella cheese
In a separate bowl, whisk together the Alfredo sauce, softened cream cheese and milk.
32 ounces Alfredo sauce, 8 ounces cream cheese, 1 cup milk
Spoon 1 cup of the sauce mixture into the bottom of the baking dish.
Next, layer 3 noodles, 2 cups of the filling and 1 1/2 cups of the sauce. Repeat two more times.
Top with the remaining mozzarella cheese.
Cover with aluminum foil and bake for 60 minutes.
Remove the foil and bake an additional 15 minutes or until the cheese on top is golden brown.
Let set for 15 minutes then cut into squares and serve warm.