Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
In a small bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, dried oregano, sea salt, and black pepper to create the marinade.
Peel the sweet potato and cut it into 1/2-inch cubes, and trim the tough, woody ends off the asparagus spears.
Place the chicken breast, sweet potato cubes, and asparagus onto the prepared baking sheet in a single layer.
Drizzle the lemon-herb marinade over the chicken and vegetables, tossing the produce to coat and brushing the chicken thoroughly on both sides.
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 fork-tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to ensure the juices redistribute for maximum tenderness.