She did a lie of omission by not telling her husband that she was the one who tipped off the SEC about a crime the mother of his child did in fact commit. She didn't do anything to Sonny.
What Michael and Carly did was way worse IMHO, but your hatred for Nina will probably never allow us to agree that so might be a moot point. Michael's intention was to have Sonny thrown in prison--yet he's not ignoring him. That was the ultimate betrayal. Carly rehired the mole as a freaking babysitter. But he's not ignoring her.
