Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Peel and dice the sweet potato into 1/2-inch cubes, chop the broccoli into bite-sized florets, and slice the bell pepper into strips.
Place the chicken breast on one side of the pan and the prepared vegetables on the other side.
Drizzle the olive oil over the chicken and vegetables, then sprinkle evenly with rosemary, thyme, garlic powder, salt, and pepper.
Toss the vegetables with your hands or tongs to ensure they are well-coated, and rub the seasoning into both sides of the chicken.
Roast in the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and slightly caramelized.
Let the chicken rest for 5 minutes before slicing to keep it juicy, then serve alongside the roasted vegetables.