If you need to cook the chicken in the slow cooker, cover it with water 4 hours on low then shred. Use a rotisserie chicken breast or even canned chicken works here.
In a mini chopper, chop all the veggies, then add the chicken and pulse a few times.
Transfer to a bowl and mix with the mayo and hot sauce, adding more to taste.
To serve, spoon into lettuce wraps and garnish with red onion, celery leaves and more hot sauce.