I know this thread is older and some may have already figured out how to save BSV to cold storage. But just in case you haven't, I finally figured out how to save it to Nano S. I downloaded Electrum SV and linked my Nano S to it. Electrum SV is a hard wallet for BSV and when you link Nano S (or other devices) it will save to them. Just be sure to research your storage device's compatibility to Electrum SV and if you need to split the coins prior to sending them.