1. In a bowl, combine the chicken, onion,
mayonnaise, salt, black
pepper and garlic powder. Stir to blend well. Chill.
2. Assemble
the sandwiches. Place the red leaf lettuce on a slice
of bread. Top with the chicken spread and then the avocado
slices and then the other slice of bread. Slice in half. Repeat
with the other slices of bread.