How do I stop the notifications from popping up? First of all this is happening because of some site you went to that attached this malicious code that then popups advertising to you. Be very careful once you fix this and pay attention to what sites you are visiting so you can pinpoint where you are receiving this malware from and then you should STOP using that site.
Fix: Open Chrome>Settings>Settings>Advanced>Privacy and Security>Content Settings>Notifications Once there look through the allowed notifications and block or delete (by clicking on the three dots to the right of the notification) the ones that you do not want to receive notifications from.