My experience has been the same. I have found it much easier to write good Nim and F# code with Claide Code, than say modern Python with type hints everywhere.

Both Nim and F# have strong types and strict compilers (arguably more strict in case of F#). These factors matter a lot more than how much code there is for the LLM to train on. And there probably is less ostensibly bad Nim and F# code out there than old Python code written by people who were not really developers, so the training data set is higher quality.