In season 2, episode 4, Blood in the streets. Nick goes into a tent with a walker behind him. He kills it, drags it into the tent and then cuts it open and smears it's blood on his face. He gags and starts again smearing the blood in his arms. When they show this he has a shirt on with cut off sleeves and then he exits the tent with the sleeves intact.
When Nick first meets Luis Flores, he says "Don't shoot", but this has obviously been dubbed in as his lips are saying different words.