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 1-inch bite-sized cubes and chop the red bell pepper into similar sized squares.
In a small mixing bowl, whisk together the extra virgin olive oil, lemon juice, lemon zest, dried oregano, garlic powder, sea salt, and black pepper.
Place the chicken cubes, broccoli florets, and bell pepper pieces onto the prepared sheet pan.
Pour the lemon-herb dressing over the chicken and vegetables, then toss thoroughly with your hands or tongs to ensure every piece is well coated.
Spread the mixture into a single even layer, ensuring the chicken and vegetables aren't overcrowded so they roast rather than steam.
Roast in the center of the oven for 18 to 22 minutes, or until the chicken is cooked through and the vegetables are tender with slightly charred edges.