1.Make buttermilk dressing. Whisk ingredients in a small bowl until combined, season to taste.
2.Combine chicken, chilli, salt and oil in a large bowl. Cook chicken on a heated oiled grill plate (or grill or barbecue), over medium heat, for 3 minutes each side or until cooked through. Clean grill plate.
3.Coat ciabatta lightly with cooking oil spray. Cook ciabatta and bacon on heated grill plate, over high heat, for 1 minute each side or until golden and crisp.
4.Arrange lettuce, chicken, bacon, tomato and avocado on plates, drizzle with dressing. Serve with ciabatta.