He's talking about possible misconduct, like what Vic's been accused of. Sabat, maybe. I somehow can't see Monica or Jamie being accused.
Possibly someone like Shane, or Shane's associates. However Nick did mention that they're known in the industry, and I doubt Shane is a known name like Sabat or Rial or Marchi or Mignogna.
The best part is Nick is not revealing the names because he doesn't have evidence, and doesn't want to spread rumors without evidence. But boy does he want to.
It's almost like the Boomerface Lawyers is acting like a responsible human being and is giving them better treatment than what they gave Vic.