Note: The Chrome browser picks up the certificate trust store from your host computer. By installing Burp's CA certificate in your computer’s built-in browser (e.g. Internet Explorer on Windows, or Safari on OS X), Chrome will automatically make use of the certificate.
If you have not already done so, configure your browser to use Burp as its proxy, and configure Burp's Proxy listener to generate CA-signed per-host certificates (this is the default setting).
You can access your systems certificate trust store at Chrome settings > HTTPS/SSL.
Or you can follow the relevant instructions for your built-in browser:
When the Burp CA certificate has been installed for your built-in browser, restart Chrome and you should be able to visit any HTTPS URL via Burp without any security warnings.