If you have a stick battery with cone threads, your options are pretty clear. These batteries also have standard 510 threads though, which can make things a little confusing. This means that you can use other non-sub-ohm tanks with a 510 connection like the Aspire Nautilus, but they stick up over the top of the threads on the battery which looks strange. The Nautilus (both the mini and the full size) comes with what are called "beauty rings" for this reason.
A beauty ring is essentially just a metal shroud that screws onto the cone threads on your stick battery to make the whole setup look nicer. Beyond just looking nicer though, they also provide some structural support. Having a huge vape tank sticking out of the top of your stick battery can provide a lot of leverage if pressure is applied, like if you were to sit on your vape, and can cause the battery to break much more easily. The structural support that a beauty ring provides doesn't stop this from happening at all, but it does make it less likely.
With standard 510 threaded tanks and larger sub-ohm tanks, keep in mind the diameter of the tank. If you have a mod that's relatively narrow and you put a wide 24mm tank like the Uwell Nunchaku on it, there will be some overhang where the tank sticks out beyond the edge of the vape mod. This isn't inherently detrimental, but most people agree that it doesn't look great and it can make your vape feel a little weird in your hand.
More important than the size of the tank compared to your mod is the power level. If you have a single battery mod that can only put out 85 watts, you don't want to put a vape tank on it that's designed to run at 95-120 watts. Take a look at what coils are available for a certain tank and see if they fall within your mod's available power range. If you're not sure how to go about this, please feel free to contact us and we can help you out.