It sounds like you've just loaded either the wrong app on your nano s or you've selected the wrong Blockchain when opening the wallet.
also, with the BTG did you set the BTG split option? or did you just select a chain?
I select BTG in the Nano Ledger, and the first time I split up the BTG coming from the Legacy chain. And it worked, and I could see my BTG. Then I did not check for a while, and I went back to check and now my BTG is gone, even though I chose Legacy chain.