I'm absolutely certain this is why he refuses to stream. He knows that that's how he gave himself away the last time he got his collar felt. He obviously thought he didn't appear intoxicated when he was swaying and babbling and beating his meat, all while sporting a beak full of white powder for the camera.
Now, he has to be thinking, "How did they figure it out then, when I was obviously sober to all intents and purposes. I'd just had a little livener to take the edge off the booze. I wasn't particularly wasted. Not like I get when I know I'm off camera. Given that, if I appear again, somebody's bound to figure it out. Enough people know what the effects of drugs like. I know, I'll wait until there's a day when I'm sober and I'll stream then."
But Nick can't manage a day sober.