If it says (nf_tables), you are using the compatibility layer from the iptables-nft package.
It works quite well. Apps like Docker that inserts rules using the legacy iptables syntax are oblivious to the fact that they are actually inserting nftables rules.
It also provides an easy migration path. Insert your old rules using your iptables script then list them in the new syntax using nft list ruleset.
The problem is that it works so well that it seems most users just stayed with the iptables syntax and did not bother migrating at all.