I usually try to pop into the debugger from within unit or integration tests, but have found this to be very slow and unreliable when doing it over a port. Have you found your experience to be different?What is your setup to debug mocha.js (or another framework) tests in chrome?
You should give VSCode a try. I was pleasently surprised about the quality of the debugger. A part from the UI I didn't have any other complaints.
If you run your node code from electron you already have access to DevTools. It's really useful.