01 - Preheat the oven to 425°F. Line a large sheet pan with parchment paper.
02 - Toss the chicken pieces with olive oil, smoked paprika, garlic powder, oregano, salt, pepper, and lemon juice until evenly coated.
03 - Arrange the seasoned chicken on one half of the prepared sheet pan.
04 - Toss the red onion, bell peppers, and cherry tomatoes with olive oil, salt, and pepper.
05 - Spread the vegetables on the other half of the sheet pan, keeping them separate from the chicken.
06 - Roast for 20 to 25 minutes, stirring halfway through, until the chicken is cooked through and vegetables are tender and slightly charred.
07 - Whisk together mayonnaise, Greek yogurt, parsley, dill, chives, garlic, lemon juice, onion powder, salt, and black pepper until smooth and creamy.
08 - Heat the pita breads until warm and pliable.
09 - Fill each warmed pita with shredded lettuce, roasted chicken, vegetables, a generous drizzle of herby ranch, and crumbled feta cheese. Serve immediately.