Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Prep the vegetables by trimming and halving the Brussels sprouts, peeling and slicing the carrots into rounds, and dicing the sweet potato into 1-inch cubes.
In a large mixing bowl, toss the prepared vegetables with 0.5 tablespoon of olive oil, minced garlic, and half of the salt and pepper.
Spread the vegetable mixture in a single layer across the baking sheet, leaving space in the center for the chicken.
Pat the chicken breast dry with a paper towel and rub it with the remaining 0.25 tablespoon of olive oil, rosemary, thyme, and the remaining salt and pepper.
Place the chicken breast in the center of the baking sheet and roast for 20-25 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 keep it tender and juicy.
Serve the sliced chicken alongside the roasted vegetables while warm.