We're documenting a few things we've come across the years when making Nim interact with other languages: https://github.com/status-im/nim-style-guide/pull/13 - the PR will grow a bit more over the coming weeks so see it as a preview.
Although Nim is easiest to consume from Nim, we often find ourselves in a position where we want to integrate some of the Nim work we've done in existing projects and vice versa - there are existing projects that expose excellent primitives (in rust in particular, of late, but also C of course) that we find ourselves wanting to use. The focus is on C/go/rust because those are the languages we use the most across the org.
As the PR says, the focus is on things that work today with released Nim versions, meaning Nim 1.6 (ie future plans are not really on the menu) - happy to hear any input, or if there are things specifically that you are interested in :)