This chest is the reason on some servers players may see some low level Republic players running around. On average it contains 4 to 9k credits, a green item and a blue item. So, generally in all the chest is worth about 20k credits each time you gather from it. The best way to farm this chest is to leave a character logged off here, thus why you mainly see low levels running around. I've heard of many of these players getting banned so I highly recommend NOT USING A LOW LEVEL CHARACTER.
Currently what I do to farm this chest is log off my level 50 Jedi Shadow at this location and log back on every 20 or so minutes to refresh my missions/gather the chest while I play an alt during the off time. Depending on what missions you're running you could easily double or triple your hourly income by doing this. I personally run Underworld Trading missions while I gather the chest since people are still convinced there is good gear to be made through Synthweaving.
Anyway, now to the part you are waiting for... Where the frig is this chest?
The location of this chest is in far northwestern Ilum. It's in a Republic safe zone which is why I recommend being Republic to farm it. Here is a picture of where the chest is on the map, you'll have to click it to enlarge it to get a better look. My coordinates on the map are X -512, Y -18; just incase you wanted to find it that way.
Now that you know where it is that you're going, let's take a good close look at exactly where the chest is around these coordinates. Below is a picture of me looking directly at the chest, the only mob insight is a level 50 Silver which is friendly to us Republic players. This chest is just begging to be looted!
After you pick up the goodies from the chest, refresh your missions, log back out and play an alt again for awhile! If you don't feel like playing an alt then you can always feel free to farm some Warzones or run around Ilum gathering level 50 components. There are certain perks for whichever of them that you choose, gathering materials means more money PvP means fun, decent money and a chance at getting some pimpin gear and finally leveling an alt means more Auction House slots and more Crew Skills to run missions with.
Whichever you decide I'm sure it will fit your playstyle the best. Afterall, I'm just here to tell you about the location!
All Different Yields From This Chest
Here are all of the different items I have gotten from this chest so far. I only started taking pictures at the time I made this guide, all the other times I didn't take any pictures. So expect this to be updated as I collect more chests. Also, be sure to take advantage of this location while it is still available and un-nerfed!