Hi, looking at that tutorial its uses node to call mountebank internally so to speak, not a technique I've had experience with.
At the top of that tutorial it notes.
Note: Mountebank can be used as a standalone application by installing it globally using the command npm install -g mountebank. You can then run it with the mb command and add mocks using REST requests.
Using this approach, running it with the mb command I've no issues using the nologfile option
node ./mountebank/bin/mb --configfile imposters.ejs --allowInjection --port 12003 --nologfile