[Stratos]

1. Open the console by pressing ~.
2. Type DebugMode 1 and press Enter.
3. Type dm_spawnitem xxx where the xxx is the item code for the chain and press Enter. Make sure the mouse pointer is at a spot in the ground that you can get to as the item will spawn there. Do a search in the internet for "Neverwinter Nights item codes", "Hordes of the Underdark item codes" or something similar to find the item code you seek. If you don't find it on the net, you could also open the HotU campaign in the Toolset and try to find the item there. What you are looking for is the item's tag. Write it down and exit the Toolset. Just make sure you don't any changes to it.
4. Type DebugMode 0 and press Enter to exit the debug mode.

Hope this helps.