go: http://lethalman.blogspot.it/2015/02/developing-in-golang-wi...
haskell: https://ocharles.org.uk/blog/posts/2014-02-04-how-i-develop-...
python: http://datakurre.pandala.org/2015/10/nix-for-python-develope...
node.js: http://sandervanderburg.blogspot.it/2014/10/deploying-npm-pa...
I recommend reading Luca Bruno's blog for learning Nix internals and more advanced topics.
The real problem is that creating a good intro developer experience takes sustained skilled time. I'm right now working on a similar project at GoCardless and we've got 3 engineers and a designer focused almost full-time on writing, designing, and user-testing our API tutorial. The Conda community would either have a patreon to sponsor someone to work on it, or convince a company to do that.