Place one slice of thin baby Swiss cheese into each of the 4 whole wheat pita pockets; set aside.
In a small bowl, stir together 1/2 cup plain Greek yogurt and 1 teaspoon garlic salt until smooth; set aside.
In a medium bowl, combine the 2 avocados (cut into small pieces), 6–8 quartered cherry tomatoes, juice from half a lemon, and half of the teaspoon of chopped cilantro; gently toss and set aside.
Heat 1 teaspoon extra virgin olive oil in a skillet over medium heat. Add 1/2 pound shredded cooked rotisserie chicken and cook 3–4 minutes, stirring occasionally, until heated through. Sprinkle with the remaining chopped cilantro while cooking.
Remove the chicken from heat and divide it evenly, placing about 1/4 of the chicken into each prepared pita pocket.
Drizzle the yogurt mixture over the chicken, then top with a generous spoonful of the avocado-tomato mixture inside each pita.
Serve immediately cold, or optionally grill the filled pitas in a sandwich press or on a grill for about 2 minutes to warm and lightly toast.