Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Peel and dice the sweet potato into 1-inch cubes, slice the carrots into thick rounds, and cut the red onion into wedges.
Mince the garlic cloves and finely chop the fresh rosemary and thyme leaves.
In a large mixing bowl, toss the prepared sweet potatoes, carrots, and onions with half of the avocado oil, sea salt, and black pepper.
Spread the vegetables in a single layer on the baking sheet, leaving space in the center for the chicken.
Pat the chicken breast dry with a paper towel and rub with the remaining avocado oil, minced garlic, and fresh herbs.
Place the chicken breast in the center of the baking sheet and roast for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F.
Remove from the oven and let the chicken rest for 5 minutes before slicing to ensure it stays moist and tender.