Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Prepare the vegetables by peeling and dicing the sweet potato into 1-inch cubes and slicing the carrots into 1/2-inch thick rounds.
Mince the garlic cloves and finely chop the fresh rosemary and thyme leaves.
In a large mixing bowl, combine the chicken breast, diced sweet potatoes, and carrots.
Drizzle with olive oil and sprinkle with the minced garlic, chopped herbs, sea salt, and black pepper, tossing thoroughly to ensure everything is well-coated.
Arrange the chicken and vegetables in a single layer on the prepared baking sheet, making sure not to overcrowd the pan so the vegetables roast rather than steam.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the root vegetables are tender and golden brown.
Remove from the oven and allow the chicken to rest for 5 minutes before slicing to keep it juicy, then serve immediately.