Start by bringing a large pot of salted water to a boil. Once boiling, add the rotini or penne pasta and cook according to the package instructions until al dente, usually 8-10 minutes. Drain the pasta in a colander and set aside.
In a large skillet, heat the olive oil over medium heat. Once hot, add the finely chopped onion. Sauté for about 3-4 minutes, stirring frequently, until the onion becomes translucent and soft. Next, add the minced garlic and continue to sauté for another minute, just until fragrant.
Incorporate the shredded cooked chicken into the skillet, followed by the buffalo sauce. Stir everything together until the chicken is evenly coated with the sauce. Allow the mixture to simmer for about 3-5 minutes, just until the chicken is heated through.
Lower the heat to low and gently pour in the heavy cream and sour cream. Stir constantly for a few minutes until the mixture becomes smooth and creamy. Then, add the grated Parmesan cheese, stirring until it's fully melted and blended into the sauce. Taste and adjust the seasoning with salt and black pepper as needed.
Carefully fold the cooked pasta into the skillet with the creamy buffalo chicken sauce. Use a spatula to gently toss everything together, ensuring each piece of pasta is well-coated in the rich sauce.
Remove the skillet from heat. Serve the spicy creamy buffalo chicken pasta hot, garnishing each plate with chopped green onions. If desired, sprinkle crumbled blue cheese over the top for an extra layer of flavor.
Notes
Adjust the buffalo sauce to your preferred spice level.