Creating this Chicken Ranch Pasta Bake is an uncomplicated process if you follow these steps:

1. Preheat the oven to 350°F (175°C).
2. Cook the pasta according to package instructions until al dente. Drain and set aside.
3. In a large mixing bowl, combine the cooked chicken, ranch dressing, milk, garlic powder, onion powder, dried parsley, salt, and pepper. Mix well.
4. Add the cooked pasta to the mixture and stir until fully coated.
5. Pour half of the pasta mixture into a 9×13 inch baking dish, spreading it evenly.
6. Sprinkle half of the cheddar and mozzarella cheese over the first layer.
7. Pour the remaining pasta mixture into the baking dish, then top with the remaining cheese.
8. Cover the dish with aluminum foil and bake in the preheated oven for 20 minutes.
9. Remove the foil and bake for an additional 5-10 minutes, or until the cheese is melted and bubbly.
10. Remove from the oven and let it cool for a few minutes before serving. Garnish with diced green onions if desired.

These steps are designed to guide you through creating this ultimate Chicken Ranch Pasta Bake effortlessly.