Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Wash and halve the baby potatoes, slice the carrots into rounds, and chop the broccoli into bite-sized florets.
In a large bowl, toss the potatoes, carrots, and broccoli with half of the olive oil, half of the sea salt, and half of the black pepper.
In a small ramekin, mince the garlic and combine it with the remaining olive oil, rosemary, thyme, and the rest of the salt and pepper.
Pat the chicken breast dry with a paper towel and rub the garlic-herb oil mixture evenly over all sides of the meat.
Arrange the chicken and the seasoned vegetables in a single layer on the prepared sheet pan, ensuring they aren't overcrowded to allow for proper browning.
Roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the potatoes are fork-tender and golden.
Remove from the oven, drizzle the lemon juice over the chicken and vegetables for a bright finish, and let the meat rest for 5 minutes before slicing.