Here is an REPL at Replit.com working Nim v 1.4.8
A couple of snippets from rosettacode.org works at Replit. VS Code with the three Nim extensions don't seem to have an REPL. Replit.com is the best for trying out some Nim code?
Here is Wandbox front-end for Visual Studio Code. https://github.com/wraith13/wandbox-vscode
Wandbox is a online compiler that provides API and we can create plugins that send code to Wandbox and download the result.
I don't use Visual Studio Code but use neovim. I use wandbox-vim plugin in neovim and I can run Nim code on Termux. https://github.com/rhysd/wandbox-vim
Current latest Nim version in wandbox is 1.6.0 but wandbox accepts pull requests that adds new compiler or new version of compiler. I have sent PRs to add previous version of Nim to wandbox-builder but it seems wandbox refactored their system recently.
Other REPL works for Nim is https://internet-of-tomohiro.netlify.app/nim/faq.en.html#tools-is-there-a-way-to-use-nim-interactivelyqmark-repl-for-nimqmark