In a large deep pot, heat olive oil or butter over medium heat. Add the cooked chicken, season with garlic powder, salt, and pepper, and sauté for 2–3 minutes until fragrant.
Pour in the chicken broth, heavy cream, and buffalo sauce; stir to combine. Add the uncooked pasta directly into the mixture.
Bring to a gentle boil, then reduce heat to low and simmer uncovered for 10–12 minutes until pasta is tender.
Stir in Parmesan cheese, mozzarella cheese, and cream cheese until melted and smooth.
Adjust seasoning as needed; garnish with chopped green onions or parsley before serving.