Pretty sure NWN includes an exe hak maker, but it's not very sophisticated (can be found in the utils directory).
In the past I've used nullsoft's package creator, but that involves some scripting.
Honestly the best route short of using rsync and pkzip, is to simply use 7 zip to compress your haks and then distribute. The only problem is if you make even a small change someone has to download the entirety of that hak again. The EXE system also has that against it. There isn't a good download manager to simply update contents.
You may wish to look at a svn repository, or maybe even the Worldgate software designed for NWN.
Ideal way which I mean to do some day would be to write rsync and pkzip routines so that when a player tries to log in it will just update the contents inside the hak, but I will have to find serious time to devote to that.