Nasser is like Dorian and obviously still takes shots every now and again. My guess is that he can be 300 at 12% body fat (or whatever he is) with relatively modest cycles, say for instance 1,500 mg of drugs per week with some ancillaries on the side perhaps. 1,500 mg being "modest" given what is required for competition. Remember, Nasser's 300 pounds is not anything like his former competition 287 pounds.
Take away all the gear and he could probably maintain a fairly crisp 230 after so many years of training, eating, and juicing like a bodybuilder.