Orks are undefeatable if they spam onslaughts

Can you guys try playing with this composition and actually see if you manage to lose?1x Deadnot Dakka (flagship)4x killa15x onslaughtI played like 20 games and didn't lose once. Assuming you do the basic stuff correctly I don't see how you can defeat this. Any ideas how you'd win against this composition?Also welcoming any challengers. If you think you can win we can do a skirmish and try it.Onslaughts are just too cheap for what they give you.