In a large bowl, mix the olive oil, dried oregano, garlic powder, paprika, salt, and pepper to create a marinade.
Add the chicken thighs to the marinade, ensuring they are well coated. Let them marinate for at least 15 minutes (or up to 2 hours in the refrigerator for more flavor).
While the chicken is marinating, prepare the veggies: in another bowl, combine the sliced red bell pepper, zucchini, red onion, and cherry tomatoes. Drizzle with a little olive oil, and a pinch of salt and pepper, then toss to combine.
On a large baking sheet lined with parchment paper, arrange the marinated chicken thighs in the center and spread the veggies around them.
Squeeze the juice of one lemon over the chicken and vegetables.
Place the baking sheet in the preheated oven and roast for 25-30 minutes, or until the chicken reaches an internal temperature of 165°F (75°C) and the veggies are tender.
Once cooked, remove from the oven and let it rest for a few minutes.
Garnish with freshly chopped parsley before serving.
Notes
For more flavor, marinate the chicken for up to 2 hours.