Yes, this is built on top of LNBits. Currently a PR, not yet merged upstream (https://github.com/lnbits/lnbits/pull/1225).
Simple docs here: https://github.com/leesalminen/lnbits-legend/blob/ad572f267a6384e2912722b79afb9afdfa24396b/lnbits/extensions/nostrnip5/README.md
Probably best to wait until the extension is merged to main.