Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Peel and dice the sweet potato into 1/2-inch cubes, then place them on one side of the baking sheet.
Place the chicken breast in the center of the pan and arrange the trimmed asparagus spears on the remaining side.
In a small glass bowl, whisk together the olive oil, minced garlic, chopped rosemary, thyme, sea salt, and black pepper.
Drizzle the herb oil mixture over the chicken, sweet potatoes, and asparagus, using your hands or a brush to ensure everything is evenly coated.
Roast in the center rack of the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the potatoes are fork-tender.
Remove from the oven and immediately drizzle the fresh lemon juice over the chicken and vegetables to brighten the dish before serving.