Try this miner - you don't need -SP 2 with the nicehash version
not working on rx 480
It didn't work for me.
the following worked (RX 470 4 GB)
Add "--opencl-platform 1" before -G like below
ethminer --opencl-platform 1 -G -S ubiq.suprnova.cc:3030 -O suprnova.1:x
Obviously replace suprnova, 1 and x with your username, worker and password.
Hope that helps