Whisk together buttermilk, mayonnaise, vinegar, chives, Worcestershire sauce, salt, garlic powder, onion powder, and pepper in a small bowl. Cover and refrigerate until ready to use.
Toss chicken with barbecue sauce in a medium bowl until coated.
Place romaine and iceberg lettuce in a large bowl, and toss to combine evenly.
Top lettuce with chicken, bacon, cheese, beans, tomatoes, chips, and scallions. Toss to combine.
Divide salad evenly among 4 bowls. Drizzle with dressing and serve immediately.
