No... for the native one, clean the 3 fields (all empty). It should execute the native emulator with the correct parameters.
(click on ESC key to have the emulator help, to know the controls)
If you prefer to use fceux (as Joe recommend), download fceux on the officiel website (fceux.com), unzip anywhere.
Then in NESMaker, Project settings, you can configure the emulator tab like this: