Well the documentation states that the nuget command-line tool does indeed work with mono

Does NuGet support Mono?

The command-line application (nuget.exe) builds and runs under Mono and allows you to create packages in Mono.

So I merrily install nuget to my home directory ~/. Run the command mono ~/nuget and get the error message:

Problem

WARNING: The runtime version supported by this application is unavailable.
Using default runtime: v2.0.50727

Solution

Turns out the simple solution is to specify the absolute .net version:

mono –runtime=v4.0.30319 NuGet.exe

 and voila!