Well this was a discouraging bit of news:
"...some bad news for those who were looking forward to the NWN Toolset. Schilling said that they've decided to cancel the port of the toolset. He told IMG that the development of the toolset had to be halted because it would have taken over a year to port it to the Mac. Schilling explained that the project to port the toolset was underway, but as the developers (Omni Group) dug deeper into the code, the estimate grew from 6 months to over a year of development time. So instead of delaying the game another 6 months, the hard decision to cancel the toolset was made."[Inside Mac Games]
At least the port of the game itself is supposedly soon forthcoming.