Cook the pasta according to package instructions; drain and set aside.
In a large skillet over medium heat, heat olive oil and add shredded chicken.
Stir in buffalo sauce, ranch dressing, cream cheese, milk, garlic powder, salt, and pepper. Mix until well combined.
Add the cooked pasta to the skillet and toss to coat with the sauce.
Stir in shredded cheddar cheese and continue cooking until melted and creamy.
Garnish with chopped green onions and serve warm.