@microbmen I would remove the mynextmanager to start for the moment. Then go to settings>>z-wave details and look for ghosts (they won't have anything in the routing column). Likely when you were setting things up you had a failed pairing and a ghost(s) and it is hurting your mesh (having multiple meshes on different devices won't affect one another)
Now that said. The main reason for no native nest control is two fold. 1, Due to the original nest api being closed off and the google api taking so long to open up, it's not been a priority and it may never be. 2. Nest is cloud based and very little cloud based things are natively supported by hubitat. Why? Because they want all automatons to work regardless of internet access. This has been a core tenant of hubitat since its inception. Most cloud based integrations have come in the form of community drivers such as mynextmanager which hubitat is not responsible for. You need to post in the author's thread on that.
Once you have your mesh cleared up, readress mynextmanager with the author. I'm sure he will work with you to straighten up that issue
Note: If you have older non plus switches (as noted by @marktheknife below) Install z-wave poller as due to licensing, the switches won't send status. Only plus devices will.