Cook the rotini pasta according to package instructions until al dente. Drain and rinse under cold water to cool.

In a large mixing bowl, combine the cooked pasta, shredded chicken, diced celery, red bell pepper, and green onions.

In a separate bowl, whisk together the buffalo sauce, ranch dressing, olive oil, garlic powder, onion powder, salt, and pepper until smooth.

Pour the dressing over the pasta mixture and toss until everything is well coated. Chill in the refrigerator for at least 30 minutes before serving.