That's actually been out for awhile now and while it makes use of NSIS, it I believe leaves 64-bit systems out in the cold. Also, I've not worked with NSIS enough to determine if it is a better choice than SFX files, which unpack on execution and delete their tracks before repacking on exit. This is a deficiency in Portable Apps ports because they're the equivalent to a trunk filled with luggage as opposed to a purse with SFX files.
If NSIS doesn't allow similar "uninstallation" then it isn't the right choice to achieve optimal portability. However, that doesn't mean the two authors couldn't collaborate on an app that hopefully would be 64-bit compatible.