i'll tell u something i live in us and never notes that...but when any body touch his nose when he talks it means he is lying or he is not Confident enough of what he talks about.

Perhaps because they are afraid to become their noses such as pinocchio nose.

This is because of an idiom in English. When you get something exactly correct, you get it "right on the nose." So when you point to your nose, it means the same thing.

I'd go for the Pinnoccio theory ! =p hahaha.... (just kidding, by the way)

I have no idea what you are talking about. I was born and raised in the USA and still live here today and never once have I touched my nose when I meant yes. I am very confused as to where you heard this happened in America.