I think both Raylib and SDL2 are not bad, and Nim bindings are available. But Pixie should be the most fun, when you do not need highest performance and can accept that it is still in an early development stage.
For highest performance we may consider blend2d, but that one has no real docs yet and no Nim bindings: <https://blend2d.com>/ I may later use blend2d myself, but for now I use GTK4 with cairo: <https://github.com/StefanSalewski/SDT>
