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 cubes and chop the broccoli, bell pepper, and zucchini into similar bite-sized pieces.
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 and chopped vegetables to the bowl, tossing thoroughly until every piece is coated in the lemon-herb mixture.
Spread the mixture in a single, even layer onto the prepared baking sheet, ensuring the pieces aren't too crowded so they roast rather than steam.
Roast for 20 to 25 minutes, tossing halfway through, until the chicken is cooked through and the vegetables are tender with lightly browned edges.