This is false.
Pokemon Uranium devs took the download links down of their own accord - they hadn't received even a Cease & Desist at this point, let alone a lawsuit. TBF - it may have been correlated to Pokemon sending C&E to a few third-party sites that were hosting Uranium alongside pirated content with less-than child-friendly advertisers. Nintendo's attitude on piracy is well-known, but they actually barely pursue legal action against piracy platforms (beyond telling them to take links down) these days either.
Let me know if you have any more questions.