Its in the HUD tab, select the HUD profile you use and click the HUD box. The HUD stats will appear on the right side, right click the stat and a window will pop-up, set the stat to vsHero stats and click apply then save HUD
I have a problem with this method: if you select “Show vs Hero only”, the stat still shows the general value, and you need to hover the mouse to see a pop-up with the vs. Hero data. Is there a way to show directly the vs. Hero data in the HUD? If not, I think this should be added as an option.