How to sort comments by likes on the facebook app? I just switched to Nexus 5 from iPhone 5.

While I was on the Facebook app on iPhone, the comments was sorted by likes, and on my new Nexus it seems it doesn't work the same.

I can change it somehow? Why does it not have the same behaviour?
I believe the answer is that the order of the comments is post specific and not dependent on the device you're reading the post on.
So while you were on your iPhone you might have seen a post in which the setting was to show the top comments first (sort by activity) and on the Nexus you must have seen a post that had the setting to show the comments in chronological order.
Reference:
http://www.adweek.com/socialtimes/facebook-sort-comments/294414