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.
Mince the garlic cloves and finely chop the fresh rosemary and thyme leaves.
Place the chicken breast and diced vegetables on the prepared baking sheet.
Drizzle everything with olive oil and sprinkle with the minced garlic, fresh herbs, sea salt, and black pepper.
Toss thoroughly with your hands or tongs to ensure every piece is well-coated in the oil and aromatics.
Spread the ingredients out in a single layer, ensuring the chicken has space around it to 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 tender and slightly browned.
Let the chicken rest for 5 minutes before slicing to keep it juicy, then serve alongside the roasted root vegetables.