Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Peel and dice the sweet potato into 1/2-inch cubes and slice the carrots into rounds.
Cut the red onion into small wedges and mince the fresh garlic cloves.
In a large mixing bowl, toss the sweet potatoes, carrots, and onions with half of the olive oil, sea salt, and black pepper.
Spread the vegetables in a single layer on one side of the prepared sheet pan.
Place the chicken breast on the other side of the pan. Rub with the remaining olive oil, minced garlic, rosemary, and thyme.
Roast in the oven for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and golden brown.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy.
Plate the sliced chicken alongside the roasted root vegetables and serve immediately.