Preheat the oven to 400°F.
In a large bowl, combine olive oil, cumin, coriander, smoked paprika, garlic powder, onion powder, turmeric, cinnamon, cayenne pepper, salt, black pepper, lemon juice, and Greek yogurt. Mix well to create a marinade.
Add the chicken thighs to the marinade, ensuring they are well coated. Cover and refrigerate for at least 30 minutes, or up to 2 hours for more flavor.
In a large oven-safe skillet or baking dish, spread the sliced onion and bell peppers evenly.
Place the marinated chicken thighs on top of the vegetables.
Bake in the preheated oven for 25-30 minutes, or until the chicken is cooked through and reaches an internal temperature of 165°F.
Remove from the oven and let it rest for 5 minutes.
Slice the chicken and serve it in pita breads or flatbreads, topped with the roasted vegetables and garnished with fresh parsley.