noun. Hmm, It's definitely a sound. And it's cute. Maybe it comes from a meerkat?
Real citation: "Zelda just ate some 'meaty loaf' and seems happier. She's hurting a lot though. She just looks at me and makes little nicker-wuffle noises"
(Oct. 14, 2009, notsusie, Twitter, http://twitter.com/notsusie/status/4874595626)
Made-up citation: "This steak is so rare it's still nicker-wuffling. Oh well, odds are I'll be somebody's steak someday--somebody like Dr. Vargas! Damn him!"