Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Peel and dice the sweet potato and carrots into 1-inch cubes, and roughly chop the red onion into similar-sized pieces.
In a small mixing bowl, whisk together the extra virgin olive oil, minced garlic, finely chopped rosemary, thyme, sea salt, and black pepper.
Place the chicken breast and the prepared chopped vegetables on the baking sheet, then drizzle the garlic-herb oil mixture over everything.
Using your hands or tongs, toss the ingredients thoroughly to ensure every piece of chicken and vegetable is evenly coated in the herb oil.
Spread the ingredients into a single layer, ensuring the chicken breast has enough space around it to roast rather than steam.
Bake for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the root vegetables are tender and slightly caramelized.
Remove from the oven and let the chicken rest for 5 minutes before slicing it against the grain and serving alongside the roasted vegetables.