Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Peel and slice the carrots into rounds, cube the parsnips into 1-inch pieces, and halve the Brussels sprouts.
In a large mixing bowl, toss the prepared vegetables with 0.5 tablespoon of olive oil, half of the salt, pepper, and minced herbs.
Pat the chicken breast dry with a paper towel and rub with the remaining 0.25 tablespoon of olive oil, minced garlic, and the rest of the herbs and seasoning.
Spread the vegetables in a single layer on the sheet pan, leaving space in the center for the chicken breast.
Place the chicken on the pan and roast for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and golden.
Remove from the oven and let the chicken rest for 5 minutes before slicing to ensure it stays juicy.
Plate the sliced chicken alongside the roasted root vegetables and serve immediately.