Did you guy created a nexus.conf in appdata?
This is what you need to put in it:
llpallowip=127.0.0.1:9325
unified=1
mining=1
yeah but i followed the old sample
which is rpcallowip, rpcpassowrd, rpcuser etc...
it work now, where i cna find the correct network hash of this?
My question is how much does 1

As I said, it is really hard to count it, because it depends on luck a lot.
But I would say with 100MHs you can find a 1-2 blocks (17NXS per block) per day and one Radeon R9 390 can do aprox. 40Mhs (you get more particular numbers if you let the miner run for a while).

from where you calculated that? the diff in this coin is confusing, i can't tell if the nethash is 300GH or that is the diff, it say "hashdiff" in getminigninfo