Yes, this is a different project, although they are related. Push Stream is a fork of my Nginx HTTP Push Module, so they both descend from the same original codebase. Push Stream uses a blocking concurrency model, whereas Nhan is completely non-blocking. In theory, this means Nchan should scale better. In practice, I haven't benchmarked it heavily enough yet to see a divergence.

Besides that, nchan and Push Stream offer different feature sets. For example, Nchan has horizontal scaling and persistence through redis, whereas push stream has customizable message transforms. There are other differences as well, but that would take a whole article to elaborate. I should probably write it soon.