so anyways. i got that normalmap to depthmap using DFT to work in Nuke too if anyone is interested:
here is the Nuke implementation. (it is a group gizmo so you do not have to worry about using it as it becomes actual nodes in your scene.)
Attachments in this post:
http://fx-td.com/houdiniandchill/wp-content/uploads/discord/20243610/23/24/image.png
http://fx-td.com/houdiniandchill/wp-content/uploads/discord/20243610/23/24/Normal2Depth.gizmo