Cook the pasta:
Preheat the oven to 375°F (190°C). Cook the pasta according to package directions until al dente. Drain and set aside.
Prepare the bacon:
Cook the bacon in a skillet over medium heat until crispy. Remove and place on a paper towel-lined plate to cool. Crumble the bacon once cooled.
Mix the sauce:
In a large mixing bowl, combine the cream cheese, ranch dressing, sour cream, garlic powder, onion powder, and black pepper. Mix until smooth and creamy.
Assemble the casserole:
Add the cooked pasta, chicken, and half of the crumbled bacon to the bowl with the sauce. Mix well to coat everything evenly.
Layer the casserole:
Spread the pasta mixture evenly into a greased 9x13-inch baking dish. Sprinkle the shredded cheddar and mozzarella cheese on top.
Bake:
Bake in the preheated oven for 20–25 minutes, or until the cheese is melted and bubbly.
Garnish and serve:
Remove the casserole from the oven and top with the remaining bacon and chopped parsley or green onions. Serve hot and enjoy!