Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Scrub the sweet potato and cut it into 1/2-inch cubes, ensuring they are uniform for even roasting.
In a small glass bowl, whisk together the extra virgin olive oil, lemon juice, lemon zest, minced garlic, chopped rosemary, thyme, salt, and pepper.
Place the chicken breast on one side of the baking sheet and the cubed sweet potatoes on the other side.
Brush half of the lemon-herb mixture over the chicken breast and toss the sweet potatoes with the remaining half until well coated.
Transfer the baking sheet to the oven and roast for 22-25 minutes, or until the chicken reaches an internal temperature of 165°F and the potatoes are golden.
While the chicken roasts, place the broccoli florets in a steamer basket over boiling water and steam for 5-6 minutes until tender-crisp.
Remove the chicken from the oven and let it rest for 5 minutes before slicing to keep it juicy.
Plate the sliced chicken alongside the roasted sweet potatoes and steamed broccoli, drizzling any remaining pan juices over the top.