Cook the Spaghetti
Cook the spaghetti according to package instructions until al dente. Drain and set aside.
Prepare the Sauce
In a large mixing bowl, combine the shredded chicken, barbecue sauce, sour cream, garlic powder, onion powder, salt, and pepper. Stir until well mixed.
Assemble the Casserole
Add the cooked spaghetti to the chicken mixture and toss until the spaghetti is evenly coated.
Transfer the mixture to a greased 9x13-inch baking dish.
Add Toppings
Sprinkle the shredded Monterey Jack cheese evenly over the top.
Scatter the crumbled over the cheese layer.
Bake
Cover the dish with aluminum foil and bake at 375°F (190°C) for 20 minutes.
Remove the foil and bake for an additional 10 minutes, or until the cheese is melted and bubbly.
Serve
Let the casserole cool for a few minutes before garnishing with fresh parsley (if desired). Serve warm and enjoy!