InXile has released a new update for Wasteland 2: Director's Cut to add modding support. The game's technical director John Alverado says that the modding tools are a work in progress and allows for users to change and override template and prefab files used in the game. More functionality will be added later.
Modders can currently change existing strings, add support for new languages, modify the stat values of NPCs, items of any kind, loot drops, and more. Players can also create new objects with unique stats. At present, new items must reference existing graphics for models and icons.
Alverado released a user guide for the current tools, which you can find here.
Modders interested in sharing their work can check out the game's official modding forums and hook up with other modders.