In a large pot of salted boiling water, add the rotini or fusilli pasta. Cook according to package instructions until al dente. Drain and let it cool for a few minutes.
While the pasta cooks, shred the cooked chicken if not done already. You can also use store-bought rotisserie chicken for convenience.
In a large mixing bowl, combine the shredded chicken, chopped celery, diced red bell pepper, grated carrot, blue cheese, and sliced green onions.
In a separate small bowl, whisk together the ranch dressing and buffalo sauce until fully combined. Taste and adjust with salt and pepper as necessary.
Add the cooled pasta to the bowl with the chicken and veggies. Pour the dressing mixture over the pasta and gently toss everything together until well mixed and coated in the sauce.
Cover the bowl and place the salad in the refrigerator for at least 30 minutes to allow the flavors to meld together.
After chilling, give the salad a good stir and taste one last time; adjust seasonings if required. Serve it chilled, garnished with additional blue cheese and green onions if desired.