Preheat the oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Scrub the sweet potato and dice into 1/2-inch cubes, then trim the tough, woody ends from the asparagus spears.
In a small bowl, whisk together the extra virgin olive oil, fresh lemon juice, minced garlic, chopped rosemary, salt, and pepper.
Place the chicken breast, sweet potato cubes, and asparagus on the baking sheet, keeping them in separate sections.
Drizzle the lemon-herb dressing over the chicken and vegetables, tossing the veggies gently to ensure they are well coated.
Roast for 20 to 25 minutes until the chicken is cooked through to 165°F and the sweet potatoes are golden and tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it succulent and flavorful.