Last time I tried nimlsp was in June-ish, using neovim.
It was an okay experience, but things broke down quickly when using macros and I got red squigglies everywhere because things rely on a certain setting. Compared to the VSCode experience, it's really lacking though.
It's certainly been getting better and the focus is also on tooling, so I'm hopeful!
[1] https://github.com/PMunch/nimlsp#readme
[2] https://github.com/emacs-lsp/lsp-mode#readme