I don't think you can get from one format to the next, and I don't expect them to adopt it at all. Unless something has changed recently V3 doesn't support the content/ or tools/ folders in the package, nor does it support pre- or post- install scripts. There are whole classes of V2 package which can't be created in V3. I expect some of this to change, but since MS went ahead and shipped V3 with Visual Studio 2015 and started publishing packages in that format, they have to be a lot more deliberate about changing behavior.
I guess my point re: Chocolatey is that they depended on a bad upstream tool that has moved in a different direction from what Chocolatey probably needs. So Chocolatey is either stuck on an old codebase - MS says they are going to maintain v2, but who thinks that is going to last? - or they are forking and maintaining themselves, which also seems unlikely as they risk giving up compatibility with all the NuGet repo software they also kind of depend on.
I guess my point re: Chocolatey is that they depended on a bad upstream tool that has moved in a different direction from what Chocolatey probably needs. So Chocolatey is either stuck on an old codebase - MS says they are going to maintain v2, but who thinks that is going to last? - or they are forking and maintaining themselves, which also seems unlikely as they risk giving up compatibility with all the NuGet repo software they also kind of depend on.