Imagine showing up in some remote hick town, and one of the locals greets you: "Na Nach Nachmu Nachmun MayUman!" you would be completely amazed and thrilled. Well basicly, just infinite times more, that's the reaction in heaven every time you say "Na Nach Nachmu Nachmun MayUman"!!!!
Now you can understand quite simply why even just saying Na Nach can do the trick, because if that local would just say Na Nach it would also get you very excited!!! So keep up the good work.
NA NACH NACHMU NACHMUN MAyUMAN!!!