The answer to the crossword is NAT, which stands for Nationals, the team that won the 2019 World Series. The Nationals are a professional baseball team based in Washington D.C. and they won their first ever World Series title in 2019. They defeated the Houston Astros in seven games to become the champions of Major League Baseball. As a result, anyone who was a member of the Nationals during the 2019 season can be considered a member of the 2019 World Series Champs.