I think you should find a home appliance outlet that sells Necht ovens, and call their service department. They can probably tell you exactly how to change the bulb. If not, you can visit the sales floor and ask them there.
If there is a problem with this, I'd call or visit a general home appliance repair shop and ask them. If they are any good, they'll know how to change the bulb, and amused enough at your situation to tell you how to do it.
Finally, if all else fails and you really need that light, I'd try to pry the cover loose with a screwdriver. That's probably how to do it anyway, but if it just damages the cover I'd keep at it until I ripped it off and could change the ^%26amp;)(%26amp;(_) bulb.
