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, crumbled bacon, cherry tomatoes, and green onions.
In a separate bowl, whisk together the ranch dressing, mayonnaise, garlic powder, onion powder, salt, and pepper until well combined.
Pour the dressing mixture over the pasta salad and toss gently until everything is evenly coated.
Fold in the shredded cheddar cheese.
Cover the salad and refrigerate for at least 30 minutes to allow the flavors to meld.
Serve chilled or at room temperature.