from "General Messages" in Qt Creator i get the messages:

LanguageClient Copilot: The command "/usr/local/bin/node /Users/jin/language-server.js" terminated with exit code 1. (see logs in ...)
LanguageClient Copilot: Unexpectedly finished.

Checking the content of the mentioned log (...)

Starting server: /usr/local/bin/node /Users/jin/.local/share/nvim/plugged/copilot.vim/dist/language-server.js Output: error: required option '--stdio' not specified

Running the command manually in terminal has the same error result. But adding the mentioned "–stdio" seems to work...

Workaround:

I created wrapper for node executable like this:

#!/bin/bash

exec /usr/local/bin/node "$1" --stdio "${@:2}" 

and set the path to this wrapper  in preferences > Copilot > Node.js path.

Now copilot works.