Preheat your oven to 400°F (200°C) and line a large rimmed sheet pan with parchment paper for easy cleanup.
Prepare the vegetables by cutting the zucchini into half-moons, slicing the bell pepper into thin strips, and breaking the broccoli into small, bite-sized florets.
Finely mince the garlic cloves and set them aside.
Place the chicken breast and all the prepared vegetables onto the sheet pan in a single layer.
Drizzle the olive oil over everything, then sprinkle the minced garlic, rosemary, thyme, sea salt, and black pepper evenly across the chicken and vegetables.
Use your hands or tongs to toss the vegetables until they are well-coated, and flip the chicken to ensure both sides are seasoned.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender with slightly caramelized edges.
Remove from the oven and let the chicken rest for 5 minutes before slicing it into strips to serve alongside the roasted vegetable medley.