Two enterprising Overwatch players figured out a way to glitch into Nepal's next level, which is fully built-out and ready to be explored.
Clarification: A previous version of this story erroneously called this an unreleased portion of the map. That reference has been removed.
Access to the second level is difficult to describe, so you'll have to watch this video to see how to try it for yourself. Basically, the next level of Nepal is over in another area outside of the first map.
Some game functions aren't available in this part of Nepal's map, such as controlling points but all the features of a map appear to be in place.
That assumes the access glitch isn't patched out in Overwatch's next update. The most recent patch (for PC; consoles will come later) buffed up new hero Ana and further nerfed McCree.