Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking dish.

Bring a large pot of salted water to a boil, then cook the spaghetti until al dente, about 8-10 minutes.

In a large mixing bowl, combine cream cheese, cream of chicken soup, sour cream, ranch seasoning, garlic powder, and black pepper until smooth.

Gently fold in shredded chicken, 1½ cups of shredded cheddar cheese, and cooked spaghetti until well-coated.

Spoon the mixture into the baking dish, spreading it evenly and topping with remaining cheddar and crumbled bacon.

Cover with aluminum foil and bake for 25 minutes, then remove foil and bake for an additional 10-15 minutes until golden.

Let the casserole rest for 5-10 minutes before slicing and serving.

Garnish with chopped parsley before serving, if desired.