All you need to display in portrait orientation on Chrome OS, is adjusting the device settings.
- Click on the Chrome Panel, on the bottom-right corner.
- Click on the Gear icon for the device settings.
- In the “Device” section, select “Display Settings”.
- A pop-up window will appear. Select either “90” or “270” to display Chrome OS in portrait mode.
- Exit with “Done”.
Read more:
How to setup OnSign TV Kiosk App in Chrome OS
How to set Android to Portrait Mode