Preheat your oven to 400°F (200°C).
Slice the sweet potato into 1/2-inch thick rounds and toss them with half of the olive oil, salt, and pepper.
Place the sweet potato rounds on a parchment-lined baking sheet and roast for 10 minutes.
Mince the garlic and finely chop the fresh rosemary and thyme.
Rub the chicken breast with the remaining olive oil, minced garlic, herbs, and the rest of the salt and pepper.
Add the chicken to the baking sheet with the sweet potatoes and roast for an additional 18-20 minutes until the chicken's internal temperature reaches 165°F.
While the chicken is finishing, steam the broccoli florets for about 5 minutes until they are tender-crisp.
Plate the chicken, sweet potatoes, and broccoli, then finish with a fresh squeeze of lemon juice over the entire dish.