At what point do I need chaos res in Hardcore?

Right now im -36% chaos res with 3.5k life and high armor reduction/capped elemental resists...does no chaos res matter?

you never need chaos resistance, unless maybe you're running hall of grandmasters maybe

This will always depend on your build. Obviously you are not doing a non-shav's low life ES-based character where chaos resistance is mandatory to not be rippy. However, From the information you gave, chaos resistance is kind of a background luxury. Most armour (I'm assuming melee) builds with high life like 5k+ don't really worry about chaos resistance. It usually ends up being that the more you have on a general build yay, but not necessary. If you can afford it, go ham and have everything capped while maintaining armour and that is about it. It will help but not necessary for high life from my experience.