Combine the sprouts and apple pieces in a large mixing bowl. In a separate bowl, whisk together the olive oil, maple syrup, and balsamic vinegar and pour over the sprouts and apple. Toss until thoroughly combined. Line a baking sheet with aluminum foil and spread the sprouts and apple onto the sheet in a single layer. Season with salt and pepper.
Roast the Brussels sprouts until tender and browned, ~10-15 minutes, turning them halfway through. Also if necessary, rotate the pan in the oven if one side is browning faster. Once cooked, remove and toss with craisins and nuts, serve hot.