For localhost only
Simply paste this in your chrome:
chrome://flags/#allow-insecure-localhost
You should see highlighted text saying:
Allow invalid certificates for resources loaded from localhost
Click Enable.
Other sites
Try typing thisisunsafe anywhere on the window, and the browser should let you visit the page.
-OR-
For a local self-signed cert that avoids arcane commands, specialized knowledge, and manual steps try mkcert from this answer.