NFL Connections #8, Answers
The full solution: all four groups and the 16 names, sorted from the easiest group to the trickiest.
Quarterback nicknames
Broadway Joe, Joe Cool, The Sheriff, Big Ben
Running back nicknames
Sweetness, Beast Mode, The Bus, The Nigerian Nightmare
Defensive nicknames
Mean Joe, Prime Time, Night Train, The Assassin
Receiver nicknames
The Playmaker, Hollywood, Megatron, Ocho Cinco