Currently, Nim fits quite well with Python but there is a project to directly emit LLVM IR from Nim and MIR might be relevant there: https://github.com/arnetheduck/nlvm

Oh, I wasn't referring to emitting LLVM IR directly from Nim, but that you should consider adding an MIR layer between your Nimic subset of Python and Nim instead of emitting Nim from Python directly. Otherwise, compilation would get difficult and adding new supported Python will get painful.