For example, the following package "gitextensions" depend on "git" and therefore wouldn't install:
http://chocolatey.org/api/v2/package/gitextensions

For a more complete solution I would have expected it to find dependencies for me (I'm trying to fix it myself, but as I'm new to the whole idea of chocolatey and nuget, and I'm not 100% positive that the only place to store dependencies is the *.nuspec file).