I've just purchased a Nikon D750 and found photoshop Express for iOS doesn't support the RAW files.
this is truely incredible that Nikon (or Adobe) aren't aupporting these files...I believe I have the most recent iOS and Photoshop Express updates.
ive seen a few converter process talked about on forums but on an iPad this is not at all how I need to do this.
Have you tried with the latest update of PS Express ? PS Express has added support fro raw files. Please check this for more info - Adobe Photoshop Express on the App Store