The Lever chest is spawned after pressing four levers in Broken Valley. See the map for the locations of the levers highlighted in black.
The locations are:
- Behind Mouse, near Jackson's Farm
- Next to Tribal Shrine
- East and just a tad south of Dreavan and the West Valley Shrine
- In the South Valley, NW of Viper's campsite, and NE of the South Valley Shrine, behind the big tree. (This one is not shown on the map!)
Once all levers have been activated you will receive a small cut-scene of the treasure chest spawning. The chest is located just south of Sosostra and can be seen in the map, highlighted in red.