You may want to look at PhysicsFS: [https://icculus.org/physfs](https://icculus.org/physfs)/
It's a C library. And it looks like someone generated a nim wrapper for it: [https://github.com/fowlmouth/physfs/blob/master/physfs.nim](https://github.com/fowlmouth/physfs/blob/master/physfs.nim)
