Preheat the grill to medium-high heat.
Season the chicken breast with a pinch of salt and pepper. Grill the chicken for about 5-6 minutes per side until fully cooked and juices run clear.
Meanwhile, wash the sweet potato and pierce it with a fork. Bake or boil the sweet potato until tender, approximately 25-30 minutes if baking or 15 minutes if boiling.
Once the sweet potato is cooked, scoop out the flesh into a bowl and mash with half of the olive oil. Season lightly with salt and pepper.
Steam the broccoli until it reaches a tender-crisp texture, about 4-5 minutes.
Separately, soft-boil the egg by placing it in boiling water for 6 minutes, then cool under running water and peel.
Plate the sweet potato mash alongside the steamed broccoli and grilled chicken. Slice the soft-boiled egg and arrange it on the side or atop the mash, then drizzle the remaining olive oil over the entire plate.
Serve warm and enjoy this nutritious, balanced lunch.