In a small bowl, stir together: ½ cup mayo, 2 Tablespoons of sour cream and 2 teaspoons of mustard.
For the sandwich:
Cut open your bread and spread the sauce lightly on both sides. Then add cheese, chicken, bacon, lettuce, tomato, onion, avocado, salt & pepper and place your bread on top!
(If using focaccia bread, cut it in half and serve. If you are using artisan bread/rolls it will make 2 servings)
Notes
Using a rotisserie chicken makes this sandwich come together much faster!