In a large bowl, combine the first 7 ingredients. In a small bowl, combine the ranch dressing, mayonnaise, Italian dressing, garlic powder and pepper; pour over chicken mixture and toss to coat. Fill each pita half with a scant 1/2 cup chicken mixture.
Test Kitchen tips
Replace the chicken with a can of chickpeas for a meatless sandwich.
Warm the pitas in the microwave just for a few seconds to make them more pliable and easier to fill without ripping.
Health Tip: Substitute reduced-fat mayo and dressings to save 60 calories and 8g fat per serving.