I haven't done much research on the Lightning Network. I'm familiar with crypto-currency and was active with it before Lightning became widely used. Then took a break for a while. Looks like I have some catching up to do.

I also really like the straightforward, cash-like utility of Monero.

Looks like the nostr #NIP15 allows for payment to be handled however you like, so Monero or even a credit card payment will work for a decentralized marketplace.