Welcome to Librarium Online!
I play a guy that has an all cav WOC army and i cant beat him any suggestions
Lots of magic and fanatics.
Take real big units of 30+
The spells that dont give armour saves are always really good.
Although Im a night goblin player, thats how i take chaos with good results often, i never play orcs so im not sure what would be useful from that half
Fanatics, doom divers, rock lobbers and anything else that doesn't allow armour save.
Stick your general in a boar unit, give the unit gorks waagh banner, call the waagh an use the banner to get the jump on them.
Use small units of wolf/spider riders to re-direct/flee charges.
Deploy back, to maximise the time you'll get to shoot them down.
The all cavalry WOC list is a tough one, you just have to be patient against it, an beat it from afar.
Well all cav. like biadetic said fanatics would be a pain for him and bolt throwers is a great thing to!! They cheap and only take ½ a choice.
If you go with a "hardcore" goblin army taking: max shamans, 3-4 units of nigth goblins, 6-8 bolt throwers and 2 doom drivers or 2 giants. You should have a good chance.