Cook the lasagna noodles according to package instructions until al dente. Drain and set aside.
In a mixing bowl, combine the cooked chicken, ricotta cheese, garlic powder, Italian seasoning, salt, pepper, and chopped spinach until well mixed.
Spread a thin layer of alfredo sauce on the bottom of a 9x13 inch baking dish to prevent sticking.
Layer 4 lasagna noodles over the sauce, followed by half of the chicken mixture, and a third of the remaining alfredo sauce. Sprinkle half of the mozzarella and parmesan cheese over the top.
Repeat the layering process: another 4 noodles, the remaining chicken mixture, another third of the alfredo sauce, and the remaining mozzarella and parmesan cheese.
Place the last 4 lasagna noodles on top, spread the remaining alfredo sauce evenly over them, then sprinkle the top with any leftover cheeses.
Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes. Remove the foil and bake for an additional 15 minutes, or until golden and bubbly.
Take the lasagna out of the oven and let it sit for 10-15 minutes before slicing.
Garnish with chopped fresh parsley before serving.
Notes
Let the lasagna sit before slicing for better serving.