01 - Preheat grill or grill pan over medium-high heat.
02 - Slice chicken breasts horizontally to create 4 thin cutlets.
03 - In a bowl, toss chicken cutlets with olive oil, garlic powder, onion powder, paprika, salt, and black pepper until evenly coated.
04 - Grill chicken cutlets for 4 to 5 minutes per side until fully cooked and juices run clear. Remove from heat and allow to rest for 5 minutes, then slice into strips.
05 - In a small mixing bowl, whisk together mayonnaise, sour cream, buttermilk, minced garlic, dill, parsley, lemon juice, onion powder, and salt and pepper until smooth. Adjust seasoning to taste.
06 - Heat pita breads in a dry skillet or microwave until warm and pliable.
07 - Spread a generous spoonful of garlic ranch sauce inside each pita. Layer with romaine lettuce, cucumber, tomato, and red onion. Add sliced grilled chicken and drizzle with additional sauce as desired.
08 - Serve sandwiches immediately while warm.