These spells are worth considering:
create a centaur
place him on the PoP on the right hand side of your starting position.
create 2 elves,
and carefully get them to destroy the chaos emplacements
(they have a slightly greater range than the dragon's-breath-firing emplacements do.
allow your mana to build up, and create centaurs - have them stand at the main gate
destroy the two totems of resurrection
just behind the main gate
when you're at full strength (full creature count and full mana)
select all of your creatures, and make them head north
when the chaos wizards detect your presence, command your troops to attack one of them
(pause the game and issue commands if it makes it easier).
select half of your troops, and issue the attack on the other wizard.
if you're lucky, the wizards wil pen themselves into the tents, and be easily killed.
When both the wizards are dead, send Aurax to release the children (right click on their cages)
items worth collecting
Each wizard will drop a chaos talisman - very useful.