Never heard of running a BEC with nitro before, unless your wanting to run high voltage servos with a 6V max receiver, then the BEC is there to limit voltage to the receiver only with the lipo bypassing it to the servos. But if the receiver can handle 7.4V, then it isn't needed. Unless the...
BEC for nitro? I would think that since he's running a 2S lipo, he just needs to make sure to get a receiver that can handle 7.4V and servos that can do the same.