Ledger nano has a different derivation path so if you imported the seed from ledger to Electron cash directly then it won't show any balances.
You should find the right derivation path of the BCH wallet from Ledger nano.
I can't seem to find any solution other than repairing your broken Ledger nano or buy a new one to recover your old BCH wallet.
I suggest you move this thread here
Hardware walletsAnd maybe someone knows what is the right derivation path of your Ledger nano BCH wallet.