Avocado Chicken Salad

Name: Avocado Chicken Salad
Ingredients: ½ cup firmly packed fresh cilantro leaves and tender stems; ½ cup coarsely chopped fresh chives, plus more for garnish; ¼ cup firmly packed fresh dill fronds; 1 tablespoon drained capers; 1 teaspoon lemon zest, plus more for garnish; 1 tablespoon lemon juice; 2 cloves garlic; ¾ teaspoon salt; ½ teaspoon ground pepper; 2 ripe avocados, halved and pitted, divided; ⅓ cup mayonnaise; ¼ cup whole-milk plain strained yogurt (such as Greek-style); 3 cups shredded cooked chicken breast