In a medium-sized mixing bowl, add the pitted and peeled avocados. Use a fork to mash them until they reach your desired consistency. You can make it completely smooth or leave a few chunks for extra texture.
Add the Greek yogurt and lime juice to the mashed avocado. Stir well to combine. The lime juice is essential as it adds a bright flavor and helps prevent the avocado from browning too quickly.
Fold in the shredded chicken, diced red onion, and chopped cilantro. Mix gently until the chicken is thoroughly and evenly coated with the avocado and yogurt mixture.
Add the garlic powder, salt, and black pepper. Give the salad one final toss. Taste the mixture and adjust the seasoning or add an extra squeeze of lime juice if needed.