Complex sentence: This was the city of Chicago's first professional sports championship since the Chicago Bulls won the 1998 NBA Finals and the first championship (other than the Bulls) since the Chicago Bears won Super Bowl XX in 1985-86.
Split into simpler sentences: This was the city of Chicago's first professional sports championship since the Chicago Bulls won the 1998 NBA Finals. And the first championship other than the Bulls since the Chicago Bears won Super Bowl XX in 1985-86.