Actually, no contest pleas are the same thing as guilty pleas, as far as the criminal system is concerned. (Most judges have a special extra little bit they add to their usual spiel when they get a nolo, explicitly letting the defendant know exactly that. Most Tahl forms also have this somewhere.)

I hear that there may be a difference in civil court. I'm not sure--I practice criminal law, and criminal law only. If there was a lawsuit, it might be different, though.
 

The technical meaning of "no contest" is that he is willing to accept the court's findings without contest. It is not the same as a guilty plea, but the defendant is usually found guilty.