Preheat oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Cut the chicken breast into bite-sized cubes and chop the broccoli, bell pepper, and zucchini into uniform pieces.
In a small bowl, whisk together the olive oil, lemon juice, oregano, garlic powder, sea salt, and black pepper.
Place the chicken and vegetables on the prepared sheet pan and pour the lemon-herb dressing over them, tossing well to ensure everything is evenly coated.
Spread the mixture into a single layer to ensure even roasting and prevent steaming.
Roast for 18-22 minutes, or until the chicken is cooked through and the vegetables are tender and slightly caramelized at the edges.
Remove from the oven and serve immediately, optionally garnishing with fresh parsley or extra lemon zest.