Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Peel and dice the sweet potato and carrots into uniform 1-inch cubes, and roughly chop the red onion.
In a small bowl, whisk together the extra virgin olive oil, minced garlic, rosemary, thyme, sea salt, and black pepper.
Place the chicken breast and the chopped vegetables on the prepared baking sheet.
Drizzle the herb-oil mixture over the chicken and vegetables, tossing thoroughly with your hands to ensure every piece is well-coated.
Spread the ingredients into a single layer, ensuring the chicken is in the center and the vegetables have enough space to roast rather than steam.
Roast for 25-30 minutes, or until the chicken reaches an internal temperature of 165°F and the root vegetables are tender and golden brown.
Allow the chicken to rest for 5 minutes before slicing to lock in the juices, then serve immediately with the roasted vegetables.