In the end "Nim in Action" is very, very valuable, because every documentation is valuable, isn't it? It's not only a great learning resource but also a good way to support a core developer of nim, you know?
Anyway, if you can't afford a copy you have plenty of ressources that can get you started: [https://nim-lang.org/documentation.html](https://nim-lang.org/documentation.html) I find the "Official tutorial" and "Nim basics" an excellent starter into nim.
