Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Cut the chicken breast into 1-inch bite-sized pieces and set aside.
Chop the broccoli florets, red bell pepper, and zucchini into uniform pieces to ensure they roast evenly.
In a large mixing bowl, whisk together the olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Add the chicken and chopped vegetables to the bowl and toss thoroughly until everything is well coated with the marinade.
Spread the mixture in a single layer across the prepared baking sheet, ensuring the pieces aren't too crowded.
Roast for 18 to 22 minutes, or until the chicken is cooked through and the vegetables are tender with slightly charred edges.
Remove from the oven and serve immediately while hot, drizzling any remaining juices from the pan over the top.