That's what I had to use after installing a few other browsers in Linux. Apparently one of them had reset some of the settings. Garcon_host_browser is the link application which will pass the URL to be opened to the Chrome browser on the ChromeOS side.
unset BROWSER
xdg-settings set default-web-browser garcon_host_browser.desktop
sudo xdg-settings set default-web-browser garcon_host_browser.desktop