Where can I find examples of an NCOER/OER "Duty Description" for an Instructor and NCOIC/OIC Instructors?

Army Career Tracker. Not all career maps have it but some have hyperlinks on the duty titles which explain them and help to craft duty descriptions for your NCOERs. Just need to tailor for subordinates supervised, property value, etc.

I can't help on the NCO side, and only have images, but hopefully these will help.

I was a 91F Instructor , you can go to the Ft Lee Web site to find things , The 5th of the 80th Army reserve Page or even the 94th . I would say maintainsand update PowerPoint Presentations, maintains training aids such as ; Weapons, Gauges, Hand Tools, specialty tools, Precision measuring tools, Keeps up to Date POI, maintains INSTRUCTOR Binder, etc