After a Nano S update (up to 1.3 release), your device is wiped. You need to recover your wallet and reinstall your applications on the device itself.
Once the update achieved, you can make one choice between these 2 options:
If you have created a new wallet, your balance is now null and you don't have any operations displayed, as it is a new wallet, not your previous one. You need to reset your device and restore your existing wallet following this guide.
If you recovered your 24 words backup, and it doesn't display the right balance, please: