Preheat your oven to 425°F (220°C).
Start by peeling and cutting the sweet potato into 1-inch cubes. Toss them with half the olive oil, a pinch of salt and pepper, then spread out on a baking sheet.
Trim the asparagus ends and toss them lightly with a drizzle of olive oil, salt, and pepper. Add them to the baking sheet with the sweet potatoes.
In a small bowl, mix the lemon juice, remaining olive oil, chopped rosemary, and thyme. Season lightly with salt and pepper.
Place the 4-ounce chicken breast on a separate baking tray. Brush both sides of the chicken breast generously with the lemon herb mixture.
Place both trays in the oven. Roast the sweet potatoes and asparagus for about 20-25 minutes until tender and slightly crispy. Roast the chicken for 18-20 minutes, or until fully cooked and the internal temperature reaches 165°F (74°C).
Once cooked, let the chicken rest for a few minutes before slicing. Plate the sliced chicken alongside the roasted sweet potatoes and crispy asparagus.
Serve hot, and enjoy a delicious, balanced dinner!