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-inch cubes to ensure even roasting.
Place the chicken breast on one side of the baking sheet and arrange the chopped vegetables on the other side.
Drizzle the olive oil over both the chicken and the vegetables, ensuring every piece is lightly coated.
Evenly sprinkle the dried rosemary, garlic powder, sea salt, and black pepper across the entire sheet pan.
Use your hands or tongs to toss the vegetables and flip the chicken, making sure the seasonings are well-distributed.
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 golden-brown and tender.
Let the chicken rest for 5 minutes before slicing to keep it juicy, then serve alongside the roasted root vegetables.