In a large pot of salted boiling water, cook the penne pasta according to package instructions. Drain and set aside.
In a large skillet, heat olive oil over medium-high heat. Season the diced chicken breast with salt and pepper. Add the chicken to the skillet and cook until browned and cooked through, about 6-8 minutes.
Pour the buffalo sauce over the cooked chicken in the skillet and stir to combine. Cook for an additional 2-3 minutes until heated through.
Reduce the heat to medium-low. Add the heavy cream, shredded cheddar cheese, and cream cheese to the skillet. Stir continuously until the cheese is melted and the mixture is smooth and creamy.
Add the cooked penne pasta to the skillet and toss everything together until the pasta is well coated with the creamy buffalo sauce.
Taste and adjust seasoning with additional salt, pepper, or buffalo sauce if desired.
Remove from heat and garnish with chopped green onions and crumbled blue cheese if using.