Overall, the nature-resist gear that was released in original WoW in patch 1.11 was catch-up gear. It was released along with Naxx to help close the gap for guilds who were still dealing with trying to get certain pieces from Green Dragons and Maraudon because they were stuck on Huhuran.
To be specific, here’s a list of pieces that are not in WoW Classic 1.13.5:
We’re still considering precisely when to release this gear, given their usefulness and purpose. As with original WoW, that time will come later, after AQ is opened and being raided.