Swag Nasty means you are swagged out and when you enter the room everyone can sense the Swag Nastiness. If you are Swag Nasty you like to break things and shit on people's feelings. You walk around like you are the shit, because you are the shit. And you are the shit because you're Swag Nasty
Holy shit did you see those girls? They were hosing everyone down. How Swag Nasty!