Preheat your oven to 400°F (200°C) and line a large rimmed sheet pan with parchment paper to prevent sticking.
Cut the chicken breast into 1-inch bite-sized cubes and chop the broccoli, bell pepper, and zucchini into similar uniform sizes for even roasting.
In a small mixing bowl, whisk together the extra virgin olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper until well combined.
Place the chicken and all the chopped vegetables onto the prepared sheet pan and pour the lemon-herb dressing over them.
Use your hands or tongs to toss everything together until every piece of chicken and vegetable is thoroughly coated in the oil and spices.
Spread the mixture out into a single, even layer, making sure the pan isn't overcrowded so the ingredients roast and brown rather than steam.
Bake for 18 to 22 minutes, or until the chicken is cooked through and the vegetables are tender with slightly charred, caramelized edges.