I think you might be able to do it through nostr:nprofile1qqs9ajjs5p904ml92evlkayppdpx2n3zdrq6ejnw2wqphxrzmd62swspzemhxue69uhhyetvv9ujuvrcvd5xzapwvdhk6qgdwaehxw309aukzcn49ekk2qghwaehxw309aex2mrp0yh8x6tpd4ehgu3wvdhk6ynf30t maybe

And what's the difference between a community and a chat?

I think you have to use something like satellites.earth to make a group. Communities don't seem to be used all that much unfortunately.