Chrome often throws certificate errors for local development sites with self-signed HTTPS certificates. As of this writing, the way to get around this is to type thisisunsafe when the error appears. The Chrome team sometimes updates this bypass, when that happens, visit the Chrome codebase looking for the base64 encoded BYPASS_SEQUENCE.
Decode it using the following command, replacing BYPASS_SEQUENCE with the text you copied from the code.
echo BYPASS_SEQUENCE | base64 --decode