Cook the rotini pasta according to package instructions until al dente. Drain and set aside.
In a large skillet, melt the butter over medium heat. Add the diced onion and sauté until translucent, about 3-4 minutes. Add the minced garlic and cook for an additional 1 minute.
In a large mixing bowl, combine the cooked rotini, sautéed onion and garlic, shredded chicken (if using), ranch dressing, sour cream, half of the cheddar cheese, half of the mozzarella cheese, garlic powder, onion powder, salt, and pepper. Mix until well combined.
Transfer the mixture into a greased baking dish. Spread it evenly.
Sprinkle the remaining cheddar and mozzarella cheeses over the top. Then, add a layer of panko breadcrumbs for a crunchy topping.
Bake in the preheated oven for about 25-30 minutes or until the cheese is bubbling and the top is golden brown.
Remove from the oven and let it cool for a few minutes before serving. Garnish with chopped fresh parsley.
Notes
Feel free to add vegetables or adjust cheese types to your preference.