Step 1: Preheat the Oven
1. Preheat Oven: Preheat your oven to 425°F (220°C).

Step 2: Prepare the Chicken and Vegetables
1. Season Chicken: In a large bowl, combine the chicken strips, sliced bell peppers, and red onion. Drizzle with olive oil, garlic powder, onion powder, paprika, oregano, salt, and pepper. Toss until everything is well coated.
2. Spread on Sheet Pan: Spread the chicken and vegetable mixture in a single layer on a large baking sheet lined with parchment paper.

Step 3: Bake
1. Bake: Bake in the preheated oven for 20–25 minutes, or until the chicken is cooked through and the vegetables are tender and slightly caramelized.

Step 4: Prepare the Herby Ranch Dressing
1. Mix Ingredients: In a small bowl, whisk together the Greek yogurt, mayonnaise, lemon juice, dill, parsley, garlic powder, salt, and pepper. Adjust seasoning to taste. If you prefer a thinner dressing, stir in buttermilk or milk until desired consistency is reached.

Step 5: Assemble the Pitas
1. Warm Pitas: If desired, warm the pitas in the oven for a few minutes or on a skillet.
2. Fill Pitas: Once the chicken and vegetables are done, remove them from the oven. Fill each pita with the chicken and vegetable mixture.
3. Drizzle with Dressing: Drizzle the herby ranch dressing over the filled pitas.

Step 6: Serve
1. Enjoy: Serve immediately, garnished with extra herbs or vegetables if desired.