Check the Github link for more details about the plugin.

Short summary:
Create named chest-tiers with a command.
When a chunk is loaded, all chests are found and filled with loot based on what WorldGuard region they are in.

A guy wanted chests filled on this map https://www.planetminecraft.com/project/scale-replica-of-chernarus/ which contains 6700 chests, so this should help speed up the process. If you're in a similar situation, the plugin may be useful for you.