League of Legends (LoL) Question: Iceborn Gauntlet or Tri Force on Bruiser Nidalee Top?

Iceborn is focussed on splitpush potential and slowing while giving huge amount of mana (more than the average bruiser needs) and CDR which is always welcome. The armor stat is just bonus. The reason why Iceborn is often favorred for things such as Bruisel Nidalee is because the enemy has barely any chance to escape when Iceborn gauntlet is bought. Trinity force does not do the same thing, since trinity force only increases your movement speed, unlike reducing the enemies, therefore your allies do not benefit from it, if that makes sense. Besides that, everyone knows that Nidalee has no problems with moving at high speed :P

It makes you tanky and it slows. That's pretty much all there is to it. You usually don't need the damage from Trinity Force as much as the durability and cc from Frostfire Gauntlet.