Hello; It is my understanding that nitro works by releasing oxygen when it burns, which makes for a bigger bang and supports better alcohol cumbustion.
Both nitro and alcohol have oxygen in its molecular structure. However that molecule is the first to react to the broken bond when it burns and does noting to the metnanol. Pure nitro provides much more power than any nitro-methanol mix. Any addition of nitro reduces efficiency, not improve it. It increases power simply because it increases the mass flow through the engine. Remember power is force applied to proved work over time and force is mass * acceleration.