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 bell pepper into strips, and cutting the zucchini into half-moons.
Add the prepared vegetables to the bowl with the chicken cubes.
In a small glass jar or bowl, whisk together the extra virgin olive oil, minced garlic, dried oregano, dried thyme, sea salt, black pepper, and lemon juice until well emulsified.
Pour the herb dressing over the chicken and vegetables, then toss with your hands or a spatula to ensure every piece is thoroughly and evenly coated.
Spread the mixture across the prepared sheet pan in a single layer, making sure not to overcrowd the pan so the ingredients roast 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 caramelized, golden-brown edges.