Chapter 16: Return to Deathshead’s Compound
Once you are dropping in the water at the very beginning of the chapter, look to the left of the ladder you need to climb to see this in the water.
As you enter the compound, go all the way to the end of the first passage and look into the opening on the left to see this lying there.
After the first large fight in the large room, go down the circular stairs on the left and you will enter another large room. Look for the gold in a square bin to the right near the far end.
During the outside part of the final boss battle, use the laser on this crate in the northeast corner and the gold pot will be inside of it.