In Australian slang, "a little on the nose" is a polite way of
saying that something smells unpleasant.
In U.S. slang, "a little on-the-nose" is a way of saying
something is obvious, expected, lacking nuance and subtleness. This
version is gradually seeping into Australia as a result of the
American influence, but it is still quite unknown.
See the related links below for confirmation of the Australian
version.