Add avocados, lemon juice, celery, onion, cilantro, salt, and pepper to a bowl and mix to combine until well blended and avocado is creamy with some chunks still intact.
Add shredded chicken to the bowl and mix until fully incorporated. Taste for salt and adjust as needed.
Serve immediately.
Notes
The avocado will brown if exposed to air for too long. To store leftovers press plastic food wrap tightly to the surface of the salad to prevent any air contact.