A degroatory term for a short, ugly man. Typically used in reference to someone from the southern united states, such as Florida, who can be described as a geek and dweeb. A "natch" will typically be someone who swing dances or lindy-hops, engages in a profession such as engineering and will usually host an uninteresting blog about himself and his numerous inconsequential achievements.
Dude! I don't care about what connection speed your cell phone gets to the internet! Stop being such a natch!