I have heard some Jews say that Jesus was a rabbi. I have never heard any Jews claim that Jesus was a Cohen. And this would contradict the New Testament claim that Joseph was from the tribe of Judah.
Some people claim that Jesus had a brother, James, with a different father and that Mary was from the tribe of Levi and was a Cohen, however, neither of these two items, if true, could have the effect of making Jesus a Cohen. I cannot comment on the accuracy of these claims, however, they have no bearing on whether Jesus could have been a Cohen.
Still others claim Jesus fulfilled the same role of the Cohen, priest, by causing sins to be forgiven, however this claim is based upon an analogy, not a claim that Jesus was a member of the Cohen line.
Apologies, Buck, to discuss a minor point at length, however, all factual inaccuracies require correction.