The easiest way to do this is to enable the scratchpad in NVDA's advanced settings,
then create a file in appModules called appname.py, where appname is the name of your executable without the extension. Put this in it:

import appModuleHandler

class AppModule(appModuleHandler.AppModule):

sleepMode=True


You can also create an addon, which would be the better option if you wanted to redistribute this, but that's a bit more involved.