Hi Kiwi,
I haven't actually fought Ogres before but I'd guess that one of their biggest advantages (other than being 10ft tall and rock hard !) must be fear.
Their greatest weakness is definitely lack of ranks and low number of units.
So I think you should try to make sure that the Nauticans are not too afraid, and definitely not outnumbered !
Take loads fo Coral Hunters, they will be a right pain in the neck for the Ogres and worth their cost on a point for point basis. He should have a problem shooting them all aswell.
Also, I'd take a lot of sandgangers to hold him up while your other troops move into position for flank charges. It looks like you've already done that anyway in your list prepared for The Empire so... you might want to drop a unit of trident guard and either get:-
1) a unit of interceptors (but only for charging ! they are great when charging due to javelin throws and wrapping around but will get slaughtered if they are charged)
or you might be better off getting...
2) Some tidewatchers for the net casting (to reduce his strength) and some wavebreakers for rank bonuses and flank attacks.
How about a tripoon battery ? And a unit of crest riders to prevent him getting a charge in ? He will probably flee and countercharge but it might break up his formation and plans a bit and keep him away from your lines while you fire on him with harpoons. The tripoon battery is actually quite good value for money (in pts terms).
You could also try some poison against him, Ogre armour is expensive so they often only have a save of 5+. Deep divers with their Nautican spearguns (and a good Bs) and the Venomous Spine banner might come in handy to avoid his relatively high toughness.
You need some sort of protection from high strength attacks which I guess the Wave Breakers and Trident Guard get in the way of their scalemail -1 to hit.
Don't forget Zharc who causes fear and has a poisonous 3 bolt speargun. It's only strength 3 but he'll hit most of the time with all 3 bolts and the enemy will only get an armour save. Zharc could lead a unit of Wavebreakers.
With regards to your general you really need someone with plenty of armour and/or a ward save. I think the Crystal Crown could come in useful too. It's a toss up really between a defensive Nautican Lord or the King of the Seas (who's tough enough to stay alive and will not be going anywhere with a Ld10 and stubborrn rule, his downside is that he only has 4 attacks which is pretty low for a special character of his points cost).
Personally, I'd love you to use the King of the Seas to se how he gets on
What you definitely do need is some way to stop him taking advantage of his high movement. You could use cresters or mantarays to help out with that. There shouldn't be much shooting coming from the Ogres so a small unit of Matarays might be ok if placed away from sharp stuff and leadbelchers.
I'm getting all excited about this !