With chest in hand, right-clicking on the donkey does not put a chest on it. Donkey in question does have a saddle on it…
Everything i've read says right click the donkey with chest in hand, but that must be just for PC version.
How to put a chest on a donkey on macintosh minecraft?
Aaron
I think shift-click, or you have to be mounted to put chest on it
Fallobt