Until August 31 when Nest will be making some major changes that we don't have a lot of clear answers on... you should be able to integrate Nest with Hubitat using a user-provided series of apps.
Note: it's a large thread, but I strongly encourage you read the whole thing before getting started so you can use some of the short cuts that others have found. If I recall I was able to get it working without creating a Nest developer account, but it was a while ago...
