Preheat your oven to 375°F (190°C).
In a skillet over medium heat, combine the cooked shredded chicken, cream cheese, ranch dressing, garlic powder, onion powder, salt, and pepper. Mix until the cream cheese is melted and the ingredients are well combined.
Stir in half of the cheddar cheese and half of the mozzarella cheese, and remove from heat.
Cook the lasagna noodles according to package instructions until al dente. Drain and set aside.
In a 9x13 inch baking dish, spread a thin layer of the chicken mixture on the bottom. Then layer 4 lasagna noodles on top of the chicken mixture.
Add another layer of the chicken mixture, followed by 4 more lasagna noodles, and repeat the process until all ingredients are used, finishing with the chicken mixture on top.
Sprinkle the remaining cheddar cheese, mozzarella cheese, and chopped green onions over the top layer.
Cover the dish with aluminum foil and bake for 25 minutes.
Remove the foil and bake for an additional 20 minutes, or until the cheese is bubbly and golden.
Remove from the oven and let it sit for about 10 minutes before serving. Garnish with chopped parsley.