iptables the kernel component might run on top of netfilter (i.e. there are various `nf_` modules loaded in my kernel, some of which are being used by `iptables_` modules), though I doubt iptables the user space component relies on ntf/nftables the user space component. Could be wrong I guess (comment and I shall edit this out if I'm wrong)

As an aside, that's one of the nice things about nftables. No more conflating the user space binary, the user space format, the kernel module and so on.

My understanding is that iptables and nftables are both user interfaces to configure rule-sets in the NetFilter code, though I think that glosses over some important bits.