Just tried it out with the new years nightly of krypton and master. NFS works like usual for me in both. You need to provide way more information to get help here (at least a debug log(wiki))
AppleTV4/iPhone/iPod/iPad: HowTo find debug logs and everything else which the devs like so much: click here
HowTo setup NFS for Kodi: NFS(wiki)
HowTo configure avahi (zeroconf): Avahi_Zeroconf(wiki)
READ THE IOS FAQ!: iOS FAQ(wiki)