I am the payee for my nephew's social security, which just started receiving in December 19. do i need to claim anything on my income tax or will in get a form in mail?

No, you will not need to report your nephew's social security/survivor benefits on your tax return. The money he receives would never be reported on your tax return. As much, it would only need to be reported on your nephew's tax return if he had a filing requirement.

Thank you for your response.  I believe my nephew was working in January up until February 22, 2019 when he was a pedestrian struck by a car.  so he would have to file taxes for those few months last year he was working I assume.  

If his earned income from working is under $12,200, he is not required to file a return.

 

However, if he has a W-2 with Federal Tax withheld, he can file a return to get that amount refunded.