Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup and even roasting.
Cut the chicken breast into bite-sized 1-inch cubes and chop the broccoli, bell pepper, and zucchini into similar sizes to ensure they cook at the same rate.
In a small mixing bowl, whisk together the olive oil, lemon juice, minced garlic, dried oregano, dried thyme, sea salt, and black pepper to create the marinade.
Place the chicken cubes and chopped vegetables onto the prepared sheet pan and pour the lemon-herb mixture over the top.
Toss everything together with your hands or tongs until every piece is thoroughly coated in the oil and spices.
Spread the ingredients out into a single layer, ensuring there is space between the pieces so the vegetables roast and caramelize rather than steam.
Bake for 18 to 22 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender with slightly charred edges.
Remove the pan from the oven and let it rest for 2 minutes before serving to allow the juices to redistribute.