Reserve 1/2 cup diced avocado for later use. In a blender, place half of the remaining avocado, cucumber, tomato, onion, broth, lemon juice, salt and pepper; whirl until smooth; place in a bowl; repeat.
Just before serving: In a bowl, toss together reserved 1/2 cup avocado with the chips.
To serve: Spoon gazpacho into four soup bowls; in the center of each, spoon a small mound of the avocado-chip mixture.
If desired, top with a small cluster of greens or cilantro springs.