Well, I put twelve flights on my A123's with no regulator on an rcexel ignition v-2. So far so good.
The difference between nano and non nano 123 batteries, as I understand it simplistically, is the nano are capable of higher burst and discharge rates. Whether nano or non nano Li fe, all should work for an ignition and are probably insignificant in difference when it come to a flight pack too. Not much difference between 30 amp or 60++ amp discharge rate when it come to my airplanes.