Mastodon offers a CSV export of just the follows. The header is: "Account address,Show boosts,Notify on new posts,Languages"

So that seems to be the easiest part. Importing old posts however, sounds like it could be very tricky.

`require("fs").readFileSync("./follows.csv").split("\n").forEach((v,i)=> {if(i == 0) return; __nostr_follow_via_nip05(v.replace("@","_at_")+"@mostr.pub")})`

Dirty, yes, but you get the idea. :)