Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Cut the chicken breast into bite-sized cubes and chop the bell pepper and zucchini into similar sizes.
Place the chicken, broccoli florets, bell peppers, and zucchini into a large mixing bowl.
Drizzle the olive oil and lemon juice over the chicken and vegetables.
Sprinkle the dried oregano, garlic powder, sea salt, and black pepper over the mixture.
Toss everything together until the chicken and vegetables are thoroughly and evenly coated with the oil and spices.
Spread the mixture out in a single layer on the prepared sheet pan, ensuring the pieces are not overlapping.
Roast in the oven for 18 to 22 minutes, or until the chicken is cooked through and the vegetables are tender with slightly caramelized edges.
Remove from the oven and serve immediately while hot.