There are currently no regular nightly builds - sorry.
However, occasional builds are made available via the Binary Downloads page - follow Nightly builds link.
JMeter is distributed as a set of zip (or tar-gz) archive files. The files are called:
The nightly builds may or may not work properly - or at all.
If there is a problem with a particular version,
it may be worth reporting this on the JMeter-dev mailing list and/or trying again in a day or two.