You are asking about the library itself, not about the wrapper? I dont think that Nim can help you for that. On page gtk.org there is/was a description for windows install, but I can not access that page currently.
For the nim wrapper, Simon has sucessfully compiled the chess game as described at [http://forum.nim-lang.org/t/2198/1](http://forum.nim-lang.org///forum.nim-lang.org/t/2198/1)
