Place cooked boneless, skinless chicken breasts in a stand mixer (with paddle attachment on). Shred chicken on medium speed until finely shredded. If you want to shred by hand instead of using a mixer, use two forks.

Add the rest of the ingredients to the shredded chicken (celery, onion, brown sugar, garlic powder, salt and pepper). Stir all ingredients well, until thoroughly blended. Take a bite; add additional salt and/or pepper, as desired. Cover salad with plastic wrap, and refrigerate until ready to serve.

When ready to make sandwiches, place the chicken salad on top of lettuce leaves on sandwich bread, and serve! Keep leftover chicken salad covered in refrigerator for up to 3-4 days.