I'm sorry, I don't quite understand your question. What nukes?
Sorry bad term to use. Are there world changing spells that don't involve worldwide disaster or instawinning?
There are no instawinning spells at all. Some can give you a huge advatage, but it's nothing that a concerted effort of the other players couldn't dispell.
Unless they don't trust each other/can't cooperate - divide et impera, after all.
The world-changing spells include:
Gift of Health - troops in lands under the god's dominion have increased(up to x2) health, age slowly, and heal afflictions.
Second Sun - heat scale increases across the world
Astral Corruption - any non-blood ritual or magic item forged can attract horrors from beyond to attack the caster/smith.
The Kindly Ones - Erynies (~ three unique demonic creatures) will randomly attack enemy practitioners of blood magic and killers of women.
Purgatory - enemy undead units within the god's dominion are struck with holy fire
The Eyes of God - the caster can see all the units within his dominion, including the stealthy ones.
Perpetual Storm - a storm rages across the world. Each and every battle is fought as if the spell "storm" has been cast. Also, less income.
Sea of Ice - no movement from and to sea provinces is allowed.
Tidal Wave - all coastal provinces suffer.
Ghost Ship Armada - undead pirates will attack coastal provinces at random.
Check this list for more:http://dom3.servegame.com/wiki/Spells
Look for spells marked "ritual", and with high number of path levels.
