Preheat your oven to 400°F and line a baking sheet with parchment paper.
Trim the ends off the Brussels sprouts and slice them in half lengthwise.
Toss the sprouts on the baking sheet with olive oil, sea salt, and black pepper until evenly coated.
Roast for 20 to 25 minutes, flipping halfway through, until the edges are deeply caramelized and tender.
While the sprouts roast, dice the chicken breast into bite-sized pieces and thinly slice the prosciutto.
Heat a large non-stick skillet over medium-high heat and cook the chicken until golden brown and cooked through.
Add the prosciutto to the skillet during the last 3 minutes of cooking, stirring until it becomes slightly crisp.
Combine the roasted Brussels sprouts with the chicken and prosciutto, drizzle with balsamic glaze, and garnish with fresh thyme.