If you set the nanoflow button in a context (e.g. dataview), you have the entity of your dataview as argument in your nanoflow.
Something like this:
Repeat steps above for each button if you want for each button a separate object.
Unfortunately, you can't at the moment.
Please help implementing this by voting on https://forum.mendix.com/link/ideas/1243 and https://forum.mendix.com/link/ideas/1170