Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Peel the sweet potato and carrots, then dice them into uniform 1-inch cubes to ensure even cooking.
In a small bowl, whisk together the olive oil, minced garlic, dried thyme, dried rosemary, sea salt, and black pepper.
Place the chicken breast and the chopped vegetables onto the prepared sheet pan.
Drizzle the garlic-herb oil mixture over the chicken and vegetables, using your hands or a brush to coat every piece thoroughly.
Spread the ingredients out in a single layer, ensuring they are not crowded 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 tender and golden brown.
Let the chicken rest for 5 minutes before slicing to keep it juicy, then serve alongside the roasted root vegetables.