Nicknames come from personalities or accomplishments, our secondary has both, our LB's and D line are rotational in plays and players. Big reason a nickname doesn't stick for a unit. You had the Heater for a while before he went to the Saints but then again that one came about from his team and what he did in practice etc. In fact it's rare to hear a LB nickname as a player, most are know for being great but not given a nickname. Singletary, Butkus,Ulracher, all great players but never a nick name I can remember. The Boz was one but that was generated from his college days.
Defensive fronts have had nicknames, Steel Curtain, Fearsome Foursome, Purple People Eaters. The most notorious.
In fact units rarely get names as much as individual players do like Beastmode.
