Mental Floss had an entry that explained the background of each NBA nickname. The names and their genesis are pretty wild for some of them. On the other hand, the newest names are all the result of some stupid "name the team" contest, which generates stupid names like the Orlando Magic and Oklahoma City Thunder.
Some of the more interesting names:
The Atlanta Hawks were originally the Tri-City Blackhawks (apparently Bettendorf was still a Dorf at the time, and not yet a Stadt), named for the same Black Hawk as the Chicago Blackhawks. Although the Black Hawk War impacted Wisconsin too, when the Tri-City Blackhawks moved to Milwaukee they became the "Hawks." When they moved to St. Louis (where Black Hawk was held after his capture) they stayed the Hawks.
The Bulls allegedly were to have a name reflecting the importance of the stockyards (although the stockyards closed five years after the Bulls arrived in Chicago). The owner was thinking Matadors or Toreadors when his son allegedly told him the names were "a bunch of bull." I have my doubts.
Actually, those are about the only interesting ones.