In a large bowl, combine the shredded chicken, romaine lettuce, mixed greens, cherry tomatoes, corn, black beans, red onion, and cheddar cheese. Toss gently to mix all the ingredients evenly.
Drizzle the BBQ sauce and ranch dressing over the salad. Toss again until the salad is well coated with the dressings.
Season with salt and pepper to taste.
If using, top the salad with sliced avocado and garnish with tortilla strips for added crunch.
Serve immediately or chill in the refrigerator for about 30 minutes to let the flavors meld together.