Some Nostr client allow to redeem Ecash and send it to your Lightning wallet. A cashu wallet is needed if you want to send ecash yourself or redeem it without cashing out immediatly to LN. By redeeming the first token on eNuts (without having a mint) it will ask to add the mint of the token that is incoming. If you agree, you redeem it and have the mint associated to it in your list (from which you can cash out back to LN anytime)