These nitro engines and diesel engines run on the same type of combustion. They use compression and heat already in the cylinder to run.
That is about 50% correct. model glow engines use a catalyst fired by methanol. (your glow plug, with a platnium element like a car's catalytic converter) Pressure plays a small part, but not much. (glow engines will run fine with the plug unscrewed some, where there is VERY little pressure) If you look at the specifics, they are quite a bit different from a diesel.
there are also diesel model engines, but they do not use pump diesel. (hint, model diesel is just as expensive as glow fuel)