Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Dice the sweet potato into half-inch cubes and chop the broccoli into bite-sized florets to ensure even roasting.
In a large mixing bowl, toss the diced sweet potato, broccoli florets, and cherry tomatoes with half of the olive oil, half of the sea salt, and half of the black pepper.
Mince the garlic clove and finely chop the fresh rosemary and thyme leaves.
Pat the chicken breast dry with a paper towel, then rub it thoroughly with the remaining olive oil, minced garlic, and chopped fresh herbs.
Spread the seasoned vegetables in a single layer on one side of the prepared baking sheet and place the chicken breast on the other side.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the sweet potatoes are fork-tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy.
Drizzle the fresh lemon juice over both the chicken and the roasted vegetables just before serving for a bright, zesty finish.