Good question. Seed as such backs up only ecash - it allows, with cooperating mint, to regenerate lost ecash into new wallet.

In new wallet, new Nostr keys are always created, as the private key never leave the device.

However, as a last part of recovery process, newly installed Minibits wallet passes hash of the seed and new nostr public key to Minibits nostr address server. If match is found, corresponding nostr and lightning address is re-linked to new keys.

That way, your minibits nostr and lightning address re-appears in the new wallet. Update is finally published to default nostr relays.