Gather your ingredients including cooked chicken, ripe avocado, Greek yogurt, lime juice, garlic powder, salt, black pepper, whole grain bread, shredded cheddar cheese, and butter.

Shred your cooked chicken using two forks to pull it apart into bite-sized pieces.

In a large bowl, mash the ripe avocado and mix in the shredded chicken, Greek yogurt, lime juice, garlic powder, salt, and black pepper until well combined.

Spread the chicken and avocado mixture on the unbuttered side of four slices of whole grain bread, sprinkle with cheddar cheese, and add cilantro if using. Top with the remaining slices of bread, buttered side up.

Preheat a skillet over medium heat and grill the sandwiches for about 3-4 minutes on each side until golden brown and the cheese is melted. Slice and serve warm.