In a large pot, boil salted water and cook the pasta according to package instructions until al dente. Drain and set aside.
In a large skillet, heat olive oil over medium heat. Add chopped onion and sauté until translucent, about 3-4 minutes. Add minced garlic and sauté for an additional minute until fragrant.
Stir in the shredded chicken and buffalo sauce, mixing well to coat the chicken evenly. Let it simmer for about 3-5 minutes to heat the chicken through.
Reduce the heat to low and add the heavy cream and sour cream to the skillet, stirring constantly until the mixture is smooth and creamy. Stir in the grated Parmesan cheese until melted and well combined. Adjust seasoning with salt and pepper.
Add the cooked pasta to the skillet with the creamy buffalo chicken sauce. Gently toss everything together until the pasta is well-coated with the sauce.
Remove from heat and serve immediately, garnished with chopped green onions and crumbled blue cheese if desired.
Notes
Adjust the buffalo sauce to your spice preference.