You want to stay away from real life NFL names to avoid anything even remotely sniffing at an infringement; they're litigious as ****. However, something like colors, directions, greek lettering (alpha, omega, etc) are relatively innocuous but would still give some life to each conference/division.
One more complicated suggestion would be set conferences (ie North, South), but fluidic nicknames for each division within them that altered depending on the division success. Each division would earn a point for every team's win, half points for ties; +3 for each playoff win (with bye weeks considered a win), +6 for a championship. At the end of each season, the total point tally would degrade by half its final tally. Whichever division was in the point lead at the start of each new season would earn the top title (Dominant, Glorious, Powerhouse, Victorious, Gold, whatever), whilst the others would get increasingly worse titles (Secondary, Brave, Silver/Tertiary, Tepid, Timid, Bronze/Powderpuff).
Final suggestion, in deference to Game of Throne's return this past week, is naming each Div after one of the major houses. I call the Sandsnakes!
Last edited at 4/16/2015 5:45 pm