That's the legal system. Prosecutors have absolute immunity for charging decisions. A.B.S.O.L.U.T.E.
Nifong was sanctioned with criminal contempt, a judge-created crime, not the same as statutory crime, for withholdoing evidence and knowing the accused were innocent but running them through the wringer anyway. One day in jail.
People on the law enforcement side know that they can use the process to punishe people they don;t like, and unless they go really really overboard, there is nothing the accused can do about it. Nearly all malicious prosecution cases fail. The remedy for withholding Brady material is a new trial - which has no play in a uilty plea situation.
Nifong was disbarred.