Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Peel and cube the sweet potato into half-inch pieces to ensure they roast evenly.
Trim the tough, woody ends off the asparagus spears and set them aside.
In a small bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, oregano, salt, and pepper.
Place the chicken breast, sweet potato cubes, and asparagus on the prepared baking sheet.
Drizzle the lemon-herb mixture over the ingredients and toss with your hands until everything is well coated.
Arrange the ingredients in a single layer on the pan, ensuring the chicken is in the center for even cooking.
Roast for 20 to 25 minutes until the chicken is cooked through and the sweet potatoes are golden and tender.