keep checking those numbers every day. you recently had ammonia in there or you wouldnt have any nitrites right now. That may be why the chromis was hiding.
I was testeing every day, and after 3 days the ammonia was 0, so I tested for nitrites, they where really low, 2 days later, took sample to pet store and they said it was cycled and to add maybe 1-2 fish and some hermits. so we did.
Most tanks cycle for a couple of weeks. You are seeing a cycle now because you have increased the tank's bio load beyond what it is capable of handling. Now, the tank is experiencing it's real cycle.