Eos is the first fully-functional editor for Neverwinter Nights on Mac. Although still in the works, there are many great features available in Eos right now. For example, with Eos you can add HAK files like the Community Expansion Pack (CEP) to your mods, saves, or even the chapters from the game.
Eos also makes it easy to edit any resource stored in a Neverwinter Nights file by allowing you to export it, edit it in your favorite editor, and import it again when you're done. The imported file will replace the old one, so you can easily customize textures or portraits used by the game.