It used to work when iPad Pro was first released! Then an update destroyed the looks of the app on iPad Pro. I sent a bug report and screenshot to Chess.com several weeks ago. Hopefully, they will fix it soon.
iPad Pro optimised version?

I just bought a pro 10.5 and was looking forward to getting a bigger board in the Chess.com app. Extremely disappointed. Unused screen estate is one thing, but its also unsymmetric. They should roll out an update ASAP
Is there an iPad Pro optimised version in the pipeline? It'd be awesome to have the app use all that lovely space instead of it being squished into one corner as it is currently 😄