Ya lil nasty is a phrase you say to someone when they are being shady or bitchy. If you say Ya lil nasty to a person they are either excluding you, talking shit about you or being an asshole.
A small piece of information. Derived from the word ken, used often in the scottish language and is synonymous with knowledge.
Person 1: "Hey I don't get this shit. How do you solve this problem?"
Person 2: "I got that one. Give me some kenlets on this assignment and I'll help you w/ that one."