Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Trim the ends off the Brussels sprouts and cut them in half, then slice the chicken breast into one-inch bite-sized pieces.
In a large mixing bowl, combine the chicken, Brussels sprouts, and diced pancetta.
Drizzle with olive oil and add the minced garlic, sea salt, and black pepper, tossing until everything is evenly coated.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the sprouts are cut-side down for maximum caramelization.
Roast for 20 to 25 minutes, tossing halfway through, until the chicken is cooked through and the sprouts are golden and crisp.
Remove from the oven and immediately drizzle the balsamic glaze over the hot pan, tossing gently to coat before serving.