Princemachiavelli, too bad that you open thread in Beginners & Help, and also here. Mod delete thread posted here and move this from B&H, so my answer is also deleted.

Ledger Nano S is only supporting addresses starting with t, so addresses starting with z can not be created (at least with Ledger Live), so you can not have your ZEC in Nano S with z in any way. By data provided on ZEC official site only wallet that provide shielded addresses (z) is ZecWallet, so if info is correct Guarda wallet will not help you with your problem.

As for BTG issue, Ledger Live is only supporting SegWit addresses, and you probably have your BTG in legacy address. Because of that you can see it in Chrome app, but not in Ledger Live. When you try to send that coin from Chrome app do you get any error? I know some users have problem with forked coins in Chrome app before when they try to send coins, and one solution is to use send max option (send all), or to play with fees. Read more here.