Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Wash the sweet potato and cut it into 1-inch cubes, then trim the woody ends off the asparagus spears.
In a small bowl, whisk together the olive oil, minced garlic, rosemary, thyme, sea salt, black pepper, and the juice of half a lemon.
Place the chicken breast, sweet potato cubes, and asparagus on the prepared baking sheet.
Drizzle the herb oil mixture over the chicken and vegetables, tossing the produce slightly to ensure an even coating.
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 potatoes are golden brown.
Let the chicken rest for 5 minutes before slicing to keep it juicy, then serve immediately.