Good news! The issues with post-v1.1.1 #Mastodon on #Nanobox have been resolved (in time for v1.2 to be tagged)! Grab the latest version on the feature/nanobox branch (currently even with v1.2) and follow the instructions near the end of the README!

https://github.com/danhunsaker/mastodon/tree/feature/nanobox

Enjoy!