Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Trim the ends of the Brussels sprouts and cut them in half; dice the chicken breast into small, bite-sized pieces.
In a large mixing bowl, combine the halved Brussels sprouts, chicken pieces, diced pancetta, and minced garlic.
Drizzle the mixture with olive oil and season with sea salt and black pepper, tossing thoroughly to ensure everything is evenly coated.
Spread the ingredients in a single layer on the prepared baking sheet, ensuring the sprouts are placed 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 crispy.
Remove from the oven and immediately drizzle the balsamic glaze over the hot ingredients, tossing gently to coat before serving.