Looks like I managed to work out the answer. Thank you LightStyle for giving me the hints.
So I create an script tag with document.getElementById('nodrag').onselectstart = function() { };
inside it and append this to the body.
// Create the script to remove the nodrag from chrome
var script = document.createElement('script');
script.type='text/javascript';
script.innerHTML = "document.getElementById('nodrag').onselectstart = function() { };";
var body = document.getElementsByTagName('body')[0];
body.appendChild(script);
This might not work in traditional contexts however works a charm on a userscript. Here is the final script:
https://gist.github.com/lgoldstien/5928021