I earned the income in my 401k while living in nj but I moved to California and that is where the distribution was paid and the taxes were withheld on a 1099. Which state must I report this income to.

You report the income to CA assuming that you were living in CA when the distribution check was sent to you. The 1099-R form that you should have received form the plan administrator should show your CA addess.

It would be an absolute nightmare if we had to report IRA or 401(k) distributions as income to the state(s) we lived in at the time we contributed to the plan(s)!