What's The 'N' Stand For On The Side of the Nebraska Football Helmet?

It's probably not something that you in-state Husker fans hear often, but for us Nebraskans living out of state, it's something that happens all too common. You're introduced to someone, introduced as a Husker fan, and they get all giddy as if they've been staying up late at night for the chance to tell you a Nebraska joke: 

"You know what the "N" stands for on the side of the Nebraska football helmet?"

I always pause before I hit them with a comeback. It's a mistake as they take the hesitation as a sign that I’m waiting to hear the punch line. What's really happening is that I’m glancing around the area to see if no one is looking so that I could kill them and quickly dispose of the body.

And so they hit me with the punch line:

"It stands for Knowledge".

To which I normally respond,

"No, it stands for ‘Not like I haven’t heard that 300,000 times already."

Then I kill them with my bare hands. Unless they’re from Colorado. Then I kill them with my bare hands slowly.

In the 90’s, my response was:

It stands for 'National Champions'
 
but unfortunately that hasn't been the case for a while, so I've gone back to serial killing. Seems to me I need a better response, although for some reason people keep offering to become my next victim.

Ideas welcome.