There is no prosecutor involved here. She is being civilly sued for defamation. She might go to jail if she defies a subpoena to turn over internal records that include confidential sources.
Overall it seems like the ex governor might actually have a leg to stand on in court, but the bar for defamation is high. I think it’s unlikely that, if this went to court, the ex governor would win. I expect this to be settled before actually being argued in court, though.