Block Twitch adds with uBlock Origin

Navigate to the uBlock Origin Dashboard (the extension options)
Under the My filters tab add twitch.tv##+js(twitch-videoad).
Under the Settings tab, enable I am an advanced user, then click the cog that appears. Modify the value of userResourcesLocation from unset to the full url of the solution you wish to use (if a url is already in use, add a space after the existing url). e.g. userResourcesLocation https://github.com/pixeltris/TwitchAdSolutions/raw/master/notify-strip/notify-strip-ublock-origin.js
To ensure uBlock Origin loads the script I recommend that you disable/enable the uBlock Origin extension (or restart your browser).

To stop using a script remove the filter and make the url unset.