In fact, technically it wouldn't be a RNC if you made use of the gi. The clue is in the name :-D
RNC is hard to get in the gi as well. Too much friction. It's much, much easier to get the arm around the neck properly in no-gi.
In a gi I'll generally try and get the collar choke if I have back mount rather than try a RNC at all.
Oh, you can do a rear naked choke without any part involved wearing a t-shirt or Gi.
In fact, technically it wouldn't be a RNC if you made use of the gi. The clue is in the name :-D
RNC is hard to get in the gi as well. Too much friction. It's much, much easier to get the arm around the neck properly in no-gi.
In a gi I'll generally try and get the collar choke if I have back mount rather than try a RNC at all.