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 uniform 1-inch cubes and place them into a large mixing bowl.
Prepare the vegetables by chopping the broccoli into bite-sized florets, slicing the red bell pepper into strips, and cutting the zucchini into half-moons.
Add all the prepared vegetables into the bowl with the chicken pieces.
In a small ramekin, whisk together the extra virgin olive oil, lemon juice, lemon zest, dried oregano, garlic powder, sea salt, and black pepper.
Pour the lemon-herb mixture over the chicken and vegetables, tossing thoroughly with your hands or tongs until every piece is evenly coated.
Spread the mixture out onto the prepared sheet pan in a single layer, making sure not to overcrowd the pan so the ingredients roast instead of steam.
Bake 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, optionally garnishing with fresh parsley or extra lemon wedges.