Add the chicken breasts to a large pot and fill it with 4 cups of water and 1 tsp of salt. You want to make sure the chicken is covered by the water so add a bit more if needed.
Bring the water to a boil then reduce the heat to low and simmer 15 - 20 minutes or until the chicken is cooked through to 160°F. You can skim the foam off the water and discard it.
Once the chicken is cooked, remove the breasts from the pot and placed them onto a plate and let them cool.
Cut the celery into small chunks measuring 1/4 cup and set it aside.
Add the chicken to the food processor and pulse a few times, then add the 1/4 cup of the celery to the food processor. Continue to pulse until the chicken is finely shredded and in very small pieces.
Remove the chicken/celery mixture from the food processor and place it into a bowl.
Add 3/4 tsp of garlic powder, 1/4 tsp of onion powder, 1/4 tsp of black pepper, 1/2 tsp of fine sea salt and 3/4 cups of mayo to the chicken. Stir to combine.
Add more mayo if you want it extra creamy or more salt if needed. Taste and adjust any seasonings.
Place the chicken salad into the refrigerator for 2-3 hrs or overnight for the flavors to develop.