Is your box a Mi Box? I have found that not all apps show up in the Play Store because they tailor them for different box models. If they haven't tailored one for your box, it won't show up or will be greyed out saying it's not compatible.
There is an .apk available taken from the Nvidia Shield. It's an older version but may be the best you can get: ABCiview_4.0.0_NvidiaShield.apk -
Bookmarks