Cook the rotini in a large pot of generously salted water until al dente. Drain and rinse under cold water until completely cooled.
Place the diced chicken in a medium bowl. Sprinkle with the BBQ seasoning and toss with 2 tablespoons barbecue sauce until evenly coated.
In a separate bowl, whisk together the ranch dressing, barbecue sauce, sour cream, apple cider vinegar, lime juice, Dijon mustard, smoked paprika, garlic powder, onion powder, salt, and pepper until smooth.
Reserve about ⅓ cup of the dressing for later.
In a large mixing bowl, combine the cooled pasta, chicken, corn, tomatoes, bell pepper, celery, red onion, cheddar cheese, bacon, green onions, and parsley.
Pour the remaining dressing over the salad and toss until everything is thoroughly coated.
Cover and refrigerate for at least 30 minutes to allow the flavors to develop.
Just before serving, stir in the reserved dressing to bring back the creamy texture.
Garnish with extra green onions, parsley, and a light drizzle of barbecue sauce if desired.