Preheat oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Chop the chicken breast into bite-sized cubes and slice the zucchini and bell pepper into even pieces.
Place the chicken, broccoli, zucchini, and bell pepper onto the prepared sheet pan.
In a small bowl, whisk together the olive oil, lemon juice, oregano, garlic powder, salt, and pepper.
Drizzle the lemon-herb mixture over the chicken and vegetables, tossing well to ensure everything is evenly coated.
Spread the ingredients out in a single layer to ensure even roasting and prevent steaming.
Roast for 20-25 minutes, or until the chicken is cooked through and the vegetables are tender and lightly charred.
Serve immediately, optionally garnished with fresh parsley or extra lemon wedges.