What does tu chez mean?

It means point taken or "ahh, you got me there" ---------------------------------------------------------- Additional info, by another user: It is actually "touché", which is used in fencing (sword fighting sport) as an acknowledgement of being hit by your opponent. I believe it is derived from the the French word for touched, as in "you have touched me with your sword". Nowadays it is also used when admitting defeat in conversation, such as when somebody says something unkind to you, but you cannot deny its accuracy... "touché".