Preheat your oven to 400°F (200°C) and line a large rimmed sheet pan with parchment paper for easy cleanup.
Cut the chicken breast into uniform 1-inch pieces and slice the zucchini into half-moons; chop the bell pepper into bite-sized squares.
In a small bowl, whisk together the extra virgin olive oil, lemon juice, lemon zest, dried oregano, garlic powder, sea salt, and black pepper.
Place the chicken, broccoli, bell peppers, and zucchini onto the prepared sheet pan.
Drizzle the lemon-herb dressing over the chicken and vegetables, then toss with your hands or tongs until every piece is thoroughly coated.
Spread the ingredients out into a single layer, ensuring they aren't 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 and slightly caramelized at the edges.