The four teams in UEFA Nations League 2026-27 League B Group B4—Poland, Bosnia and Herzegovina, Romania, and Sweden—enter the league phase with comparable squad depth and recent form, producing tightly bunched implied probabilities around 26-28% for each as group winner. All sides feature experienced forwards and solid defensive structures capable of securing points across the six-match schedule that begins later this month. Poland benefits from depth at key positions and strong home support in Warsaw, while Bosnia and Herzegovina leverage veteran leadership and recent squad stability. Romania and Sweden counter with organized pressing and set-piece threats, supported by competitive head-to-head records in prior cycles. Fixture congestion in September-October and variable travel demands add further uncertainty, leaving room for any side to claim top spot depending on early results and injury management.