I heard that it's not good to spray when the auto shifts gears, IDK if this is true or not but it makes sense. Is a window switch absolutely necessary for the reliability of an automatic transmission if you are running nitrous?

 

I wouldn't see a problem in doing it. I heard you need an Anti-Ballon stall converter if you want to spray off the line.
I would think a window switch is pretty much usless on an automatic because it is impossible to miss a gear.

BTW: I don't know much about automatics so dont take my advice seriously. Im just telling you what i think.