Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Peel the sweet potato and carrots, then dice them into uniform 1/2-inch cubes to ensure they cook at the same rate.
Place the diced vegetables on the baking sheet, drizzle with half of the olive oil, and sprinkle with half of the rosemary, salt, and pepper.
Toss the vegetables thoroughly to coat and spread them out in a single layer, leaving a space in the center for the chicken.
Rub the chicken breast with the remaining olive oil, garlic powder, rosemary, salt, and pepper until evenly coated.
Place the chicken in the center of the baking sheet and roast for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to ensure it stays juicy and flavorful.