How is NIP05 related to nip46?
Discussion
when logging into a new client you enter your nip05 and then get a prompt from your signer.
behind the scenes there is a nip46 section in .well-known/nostr.json which lists nip36 relays for each pubkey.
So I need to change my nostr.json to support that?
yes, so the client know which relay(s) to use communicate with the signer.
relay.nsec.app is a popular one even if you don't use nsec.app as the signer.
you don't have to use the same address as you list in your kind-0 but it makes sense to.