Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Peel the sweet potato and cut it into 1/2-inch cubes, then toss them on the baking sheet with half of the olive oil and a pinch of salt.
Roast the sweet potatoes for 10 minutes to ensure they become perfectly tender and caramelized.
While the potatoes roast, whisk together the lemon zest, lemon juice, minced garlic, rosemary, thyme, and the remaining olive oil in a small bowl.
Season the chicken breast on both sides with the remaining salt and pepper, then place it in the center of the baking sheet.
Drizzle half of the lemon-herb marinade over the chicken breast and return the pan to the oven for 10 minutes.
Trim the tough ends off the asparagus and add them to the pan, drizzling the remaining marinade over the spears.
Roast for a final 10 to 12 minutes until the chicken reaches an internal temperature of 165°F and the asparagus is vibrant and crisp-tender.