I don't think strains themselves make so much difference with performance. Sure, some, but think the quality of material does. More trichs is always best for vaping (and most anything else!). And, the more liquidy, clear, bulbous they are the better. Moisture content will have a big effect on how anything vapes, too. You'll probably notice a good difference between now and a few months from now with the same strain (or even stash if you're stocked up like that) just from humidity changes.
Strains do make a big difference with flavor and effect, though. I usually don't have much to chose from, but have managed to move a pretty good variety through.
The nano just really seems to bring the differences out. Simplicity, constant heat with no drawdown, simple direct short connection, incremental analog heat adjustment, all really add to the vaping experience and allow flavors to become more pronounced. Kind of think it does the same with differing effects too, but that's so subjective it's hard to say. Once you start getting tuned in to your nano enough to know how you want to adjust for a new stash after a quick taste, that all gets even better. When you have conduction and limited heat settings (solo), or a bunch of gear and air between you and the heat (EQ), or rely on draw speed for temp modulation (MFLB, vapman) it can be kind of hard to stay on top of things to keep it steady enough to get as good of a feel for strain differences. Even harder to easily adjust a little here or there for a new strain.
But which strains are best? Think that is kind of like what's the best flavor of ice cream! Go for whatever flavor and effects you're looking for. IME, nano will just make it all that much more noticeable and better.