Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Peel and dice the sweet potato into 1/2-inch cubes, slice the carrots into rounds, and chop the broccoli into bite-sized florets.
Place the chicken breast on one side of the baking sheet and arrange the sweet potatoes, carrots, and broccoli on the other side.
Drizzle the olive oil over the chicken and vegetables, ensuring everything is lightly and evenly coated.
Sprinkle the dried rosemary, dried thyme, garlic powder, sea salt, and black pepper over both the chicken and the vegetables.
Toss the vegetables with your hands or a spatula to distribute the seasonings, then ensure the chicken is coated on both sides.
Roast in the oven for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are golden and tender.
Let the chicken rest for 5 minutes before slicing to keep it juicy, then serve alongside the roasted vegetable medley.