Regenerating portion [certain blocks] of world?

Title is pretty much self-explanatory -
I would like to restore a part of the world (for example, a 50x50 village), after it has been destroyed, using a scheduler. The scheduler part is straight-forward enough, but I'm not sure where to start for regenerating blocks/chunks. Any advice or ideas are welcome, and thanks in advance!

TL;DR Any way to restore/regenerate blocks? I have no idea how to do this.