I've used Nim for most of my personal projects for the past ~2 years, and it's generally enjoyable. There are a lot of useful language features. C interop, generics, tagged unions (I always miss these in languages without them), traits (powerful duck typing), channels, generators. Metaprogramming via templates/macros if you want to get crazy. Lots of rope to hang yourself, so to speak.

I wouldn't choose to use it in production, mostly because of the developer experience. The documentation and tooling are both pretty bad, and the compiler errors can be arcane (especially when using generics, or when the error only surfaces during C compilation).