The Indus Nebula was a large nebula that was located in both the Alpha and Beta Quadrants. (PIC: "Disengage")
This nebula was only mentioned in writing.
The location of this nebula was seen on the bridge of the SS Eleos XII on what appears to be an updated chart from Star Trek: Star Charts. The nebula is a new addition to the chart. Dave Blass published pictures of the set on his website.