I found this article [http://blog.stevensanderson.com/2011/01/13/scaffold-your-aspnet-mvc-3-project-with-the-mvcscaffolding-package/], which explains how to use MVC Scaffolding
I've seen a project, that tried to implement templates for NHibernate and MVC scaffolding, but according to this thread it seems to be closed.
I think the post on Overriding T4 Templates from the same series should tell you all you need to know to switch to a repository template based on NHibernate. If you end up implementing your own, please post them somewhere :)