Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Peel and dice the sweet potato and carrots into uniform 1/2-inch cubes to ensure even cooking, and slice the red onion into thin wedges.
In a large mixing bowl, combine the diced vegetables with half of the olive oil, half of the minced garlic, and half of the chopped herbs, salt, and pepper.
Place the chicken breast on the prepared baking sheet and rub with the remaining olive oil, garlic, rosemary, thyme, salt, and pepper until well coated.
Arrange the seasoned root vegetables in a single layer around the chicken breast, ensuring they aren't overcrowded so they roast rather than steam.
Roast in the center of the oven for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are fork-tender and lightly browned.
Remove from the oven and let the chicken rest for 5 minutes before slicing to allow the juices to redistribute for maximum tenderness.