Preheat your oven to 400°F and line a large rimmed baking sheet with unbleached parchment paper for easy cleanup.
Pat the chicken breast dry with paper towels and dice into 1-inch cubes; chop the broccoli, bell pepper, and zucchini into similar bite-sized pieces.
In a small glass bowl, whisk together the extra virgin olive oil, fresh lemon juice, lemon zest, oregano, garlic powder, sea salt, and black pepper.
Arrange the chicken cubes and chopped vegetables on the prepared sheet pan, ensuring they are spread out and not overlapping.
Drizzle the lemon-herb marinade over the chicken and vegetables, then use clean hands to toss everything until every piece is well-coated.
Spread the ingredients into a single layer and roast in the center of the oven for 20 to 25 minutes, or until the chicken is cooked through and the vegetables are tender-crisp.
Remove from the oven and let rest for 2 minutes before serving to allow the juices to redistribute across the chicken.