Not the author, but probably very poorly. This seems more like a proof of concept, it's written in Python, has a very basic tree search which is very light on heuristics. And likely the NN is undertrained too, but I can't tell from the repo. In comparison Stockfish is absurdly optimised in every aspect, from its datastructures to its algorithms. Considering how long it took the LeelaZero team to get their implementation to be competitive with latest Stockfish, I'd be shocked if this thing stood a chance.

Of course, beating Stockfish is almost certainly not the goal for this project, looks more like a project to get familiar with MLX.