Preheat your oven to 425°F (220°C).
Line the baking sheet with parchment paper or spray it with cooking spray to prevent sticking.
In a large mixing bowl, combine the olive oil, garlic powder, paprika, dried oregano, salt, and pepper. Mix well to form a marinade.
Add the chicken thighs to the bowl and coat them evenly with the marinade.
Place the marinated chicken thighs on one side of the prepared baking sheet.
In the same bowl, add the broccoli, carrots, and chopped red bell pepper. Toss them in the remaining marinade until evenly coated. Spread the vegetables on the other side of the baking sheet.
Roast in the preheated oven for 25-30 minutes, or until the chicken is cooked through and the vegetables are tender.
Once done, remove from the oven and let it rest for a few minutes.
Garnish with fresh parsley if desired and serve hot.