You are right. The nest does have a cavern zone.First, by "definition", which cave "tools" love to use, every cave has a cavern. Unless you dive the site at night.
second, look at any map of eagles nest and tell me what that shaft between the basin and the big open room is. Heres a clue, "CAVERN!" ...
...I see nothing wrong with cavern divers staying within the cavern zone at Eagles nest. ....Slow down and look next time you dive there. I did.
But the question should be, should a cavern diver go there? I believe not, many other cavern zones yes, the nest is a different ball game. The narrow tube make for a small vertical cavern zone. Then there is depth (140ft to the top of the mount) and low flow. All these combined make for a challenging dive. Suppose something goes wrong and the mount silts up. You are now in a large cave at depth with one narrow tubular exit starting at 70ft and a bottom around the mount of about 200ft before it goes into tunnels.
Not the place I would want to be as a cavern diver. I slowed down and did look.....