J'ai pas trop tester cette parti de la chose, mais sur le forum une personne ma confirmé que tu perds rien en désinstallant.

Note that your Nano S can hold about 5 applications at the same time, but you can deal with many more applications - as many as stated on the Ledger Manager - by removing and installing the ones you need to manage. Removing an application won't make you lose your coins: you will be able to see your balance and transact as soon as the coin application has been installed again.