Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Cut the chicken breast into bite-sized 1-inch cubes and chop the broccoli, bell pepper, and zucchini into similar sizes to ensure even roasting.
In a large mixing bowl, whisk together the extra virgin olive oil, fresh lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Add the chicken cubes and chopped vegetables to the bowl and toss thoroughly until every piece is evenly coated with the herb marinade.
Spread the mixture in a single layer across the prepared sheet pan, ensuring the ingredients are not overcrowded so they roast rather than steam.
Bake for 18 to 22 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender-crisp with slightly browned edges.
Remove from the oven and let the dish rest for 2 minutes before serving to allow the juices to redistribute for maximum tenderness.