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 red bell pepper into strips.
Place the chicken breast on one side of the prepared baking sheet and arrange the sweet potatoes, broccoli, and peppers on the other side.
Drizzle the olive oil over the chicken and vegetables, then sprinkle everything evenly with the rosemary, thyme, garlic powder, sea salt, and black pepper.
Toss the vegetables with your hands or a spatula to ensure they are well-coated in oil and spices, and rub the seasoning into both sides of the chicken.
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 sweet potatoes are fork-tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy, then serve alongside the roasted vegetables.