A person who touches his chin during a conversation feels anxiety and discomfort. Touching the chin falls into the soothing innate nonverbal gestures when we're trying to calm down or alleviate the feelings of anxiety and tension. Women, instead of touching the chin, often play with collar in order to achieve the same calming effect.
A person who touches his nose is most often hiding something from their interlocutors. It is important to understand the context in which this action takes place because it may be that this is just about the nose leaking, or some other biological intrusion. If this action happens frequently, it may indicate interlocutor's unclean conscience.
The ear falls into soothing actions. Soothing body movements are actions that have the effect of calming the pulse when you overcome the feeling of restlessness and anxiety. If a person during a conversation starts to touch his ear, he is trying to say that that he already heard everything that was said, or that he disagrees.