Preheat the oven to 400°F (200°C) and line a heavy-duty rimmed baking sheet with parchment paper.
Distribute the prepared chicken thighs, broccoli, bell pepper, zucchini, and red onion across the baking sheet in a single layer.
In a small whisking bowl, combine the olive oil, oregano, basil, garlic powder, onion powder, salt, and black pepper.
Drizzle the herb oil mixture over the chicken and vegetables, tossing thoroughly with tongs to ensure uniform coverage.
Arrange the ingredients so they are not overcrowded, allowing for proper airflow and browning.
Roast for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F (74°C) and the vegetables are fork-tender with charred edges.
Remove from the oven and immediately garnish with grated Parmesan cheese and fresh parsley.
Allow the dish to rest for 5 minutes before serving to let juices redistribute.