New Mac, unable to get NFS to work. What am I missing?

On my old Mac mini (Mojave), I would add something like "/foo -rw 192.168.0.99" to /etc/exports, restart nfsd, and then I could connect from that IP to the Mac. On my new Mac mini (Sequoia), nfsd is there and running, but there's no /etc/exports. I tried creating it and then doing the above, but when I do showmount I get nothing: matt@mattmini2 ~ % showmount -e Exports list on localhost: I'm assuming there's a new method for doing this in Sequoia, but if so my googling is failing me. Can anyone help?