no, nitriding is a whole 'nother deal. Cryo treating is chilling the parts to very low (~-300F) temperature in a controlled fashion and holding it there while the stresses normalize and martensite forms. No chemical immersion, and it's an all-the-way-through process, not a surface hardening.
When my son and I used to race Quarter Midgets we would occasionaly buy cyrogenic treated connecting rods. It is a very real process with many touted benefits. I do not know enugh about it to comment on it technically though. Here is s ont information I found in Google: http://www.nwcryo.com/motorsports.htmlWhile I cannot vouch for the treatment I have spent money on it. We always said that if that if this weeks race winner had a dog turd on his front fender by the next week everyone would have a turd on their fender.