Preheat your oven to 400°F and line a large sheet pan with parchment paper.
Prepare the vegetables by trimming the woody ends from the asparagus, dicing the bell pepper into 1-inch pieces, and cubing the sweet potato into 1/2-inch chunks.
Place the chicken breast, sweet potato cubes, asparagus, and bell peppers onto the sheet pan in a single layer.
Drizzle the olive oil and lemon juice over the chicken and vegetables.
Sprinkle the oregano, garlic powder, sea salt, and black pepper evenly across all ingredients on the pan.
Toss the vegetables to coat thoroughly and flip the chicken to ensure it is seasoned on both sides.
Roast for 20-25 minutes until the chicken reaches an internal temperature of 165°F and the sweet potatoes are tender.
Let the chicken rest for 5 minutes before slicing to maintain juiciness, then serve with the roasted vegetables.