Preheat your oven to 400°F (200°C). In a large bowl, combine the chicken thighs with olive oil, garlic powder, onion powder, smoked paprika, ground cumin, dried oregano, salt, and pepper. Toss until the chicken is well coated with the seasoning.
Heat a large oven-safe skillet over medium-high heat. Add the seasoned chicken thighs, skin side down, and sear for about 5-7 minutes until the skin is golden brown. Flip the chicken and sear for another 5 minutes.
Remove the chicken from the skillet and set aside. In the same skillet, add the sliced onion, zucchini, and red bell pepper. Sauté for about 5 minutes until the vegetables are tender.
Return the chicken to the skillet, placing it on top of the sautéed vegetables. Transfer the skillet to the preheated oven and bake for 25-30 minutes, or until the chicken is cooked through and reaches an internal temperature of 165°F (75°C).
Once cooked, remove the skillet from the oven and let it rest for 5 minutes. Garnish with fresh parsley before serving.