Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Trim the woody ends off the Brussels sprouts and slice them in half vertically to ensure they get maximum surface area for browning.
Dice the chicken breast into uniform 1-inch cubes so they cook evenly alongside the vegetables.
Place the sprouts and chicken on the prepared baking sheet, then drizzle with olive oil and sprinkle with sea salt and black pepper.
Toss everything thoroughly with your hands to coat, then spread into a single layer, ensuring the sprouts are placed cut-side down.
Roast for 20 minutes, or until the sprouts are tender and the chicken is cooked through.
Tear the prosciutto into bite-sized ribbons and scatter them over the pan, then return to the oven for 5 more minutes until the prosciutto is shatteringly crisp.
In a small bowl, whisk together the balsamic vinegar and honey until smooth and well combined.
Remove the pan from the oven, drizzle the balsamic mixture over the hot ingredients, and toss well to create a sticky, savory glaze.