Place the shredded chicken in a medium mixing bowl. Break apart any large pieces so the chicken is evenly shredded.
In a separate small bowl, add the avocado, mayonnaise, lime juice, garlic powder, salt, and black pepper. Mash and stir until mostly smooth and creamy. A few small pieces of avocado are fine.
Add the avocado mixture to the shredded chicken. Fold everything together until the chicken is evenly coated.
Add the cilantro, red onion, and green onion. Gently fold them into the chicken salad until evenly distributed.
Taste the chicken salad and add more salt, black pepper, or lime juice as needed. For a creamier consistency, mix in an additional teaspoon of mayonnaise.
Transfer the chicken salad to a covered 16-ounce deli container. Refrigerate it for at least 20–30 minutes before serving to allow the flavors to come together.
Serve chilled in lettuce cups, on toasted bread, in a wrap, over mixed greens, or alongside crackers and sliced vegetables.
