So, the players faced off for two 10 10 games (10 minutes, plus 10 second increments). Nakamura won the first one with White, but Bu looked ready to equalize in the rematch, with an active queen against rook and knight. He was unable to figure out a way to brake Nakamura's blockade, however, and the end was tragicomic:

White's king has been running around all over the place, to no effect, but now Bu chose a less than auspicious location for the monarch: 68.Kd6?? Nxe4#. (A partial video clip from the playoff and brief interviews with Nakamura and Bu are here.)
So a fine result for Nakamura, whose 2712 TPR will push his 2679 rating a touch closer to the special and financially significant 2700 level.