There's the Nim package manager [Nimble](https://github.com/nim-lang/nimble) and its README has a section on [project structure](https://github.com/nim-lang/nimble#project-structure).
Also, if you use `nimble init` on the command line, it will create the structure for you to have an easy start. :-) The example files also have imports so you see how a file references others.
