do not ever use an es setup for hc - you will die pvm even with es improvements its just not reliable enough.
if you are going hc meet these requirements:
stacked all res so if your under conviction you wont have neg res, poison is not a real threat.
highest defense possible, i have 20k defense on my sorc using barbs bo + shout
max damage reduction
this is subjective - some use no block, 25% block 50% block, max block. i use 50% block on my sorc
never go outside town if you dont have barbs bo on and make sure your support barb has perfect gear - 56 bo on the barb, highest shout, best battle command.
you will have significantly less damage using (any build) because you are using mass 20 hp scs and not skillers
mass hp - 4500-6000 hp is a good range from mass hp scs, barbs bo + oak
hoto / ss + ber should be used at all times across all builds even nova, do not use infinity(held on char) + insight on merc for hc. its totally fine sc but hc is a different game. i would personally not build a nova sorc because of how under powered they are vs conventional builds like vita fb, vita bliz, vita light.
harden the setup with 117 fcr:
shako - not griffons, socket with um or 15 all res + useful mod like hp
maras or better 2/20 fcr + res + str caster craft amulet
ap coh
hoto - 40 res / non eth so you can use your oak charges, and hotkey your oak
trang gloves fcr + cold res
148 ss + um
spider
rings 2 x 10 fcr 40 hp dual res if possible (poison is not a res here) +str if possible or +dex if possible
30/10/tri res (poison is not tri res) + str if possible or use hotspers upgraded
switch: sometimes you are in hot and deadly elemental situations where hoto + ss+um is not enough so i have a "elemental hardened switch" it does not meet 117 fcr but you can tank a lot using silence in a crystal sword (2 all skill + 75 all res) for low str low dex and sanctuary 70 res in troll nest shield. a wiz spike is also a life saver but you might not want to put that many points into dex. if you have enough points into dex by having some block (25% or 50% block) use wiz over silence.
infinity in ca or cv / eth sa fort / cure helm or eth ral'ed andys
the logic: use hoto + ss +um for physical and most elemental damage you will face, this is your main side meeting 117 fcr (120 total so we meet fcr bp), IF you run into souls swap to your elemental switch side or if a monster has charged bolts those are very painful.
your inventory should be filled with every slot with 20 hp scs + any useful mod you can get. if you are farming items shoot for 20 hp 11(fr, cr, lr) if you can afford, 20/5's will also work. stand in conviction or calculate how much res you will have under conviction if a monster has it, does your setup meet standards? if not swap out a 20 sc and swap in a 20/11 or 20/5 until res stack under conviction for all res or for a particular res is met.
always watch your ping if you believe you have the slightest bit of latency quit, always work in private games with the lowest amount of players possible (main + support barb), avoid pkers even low level chars, they will be 30 and usually carrying a honor eth naga or a eth insight or eth bonesnap maul
always precast your char using a support barb, i wrote an autoit and later a lua script for precast spell duration timers, try and follow the same logic in you can get a warning before your bo / shout wears off in the task bar using notifications.
use your hoto's oak charges and put a hotkey on them, never step outside town if you dont have barbs bo precast + oak
never get on the character if you are over tired or your concentration is split.
some situations are just deadly, souls in throne + dolls, just exit game dont even try it. sometimes you can go to throne 2-3 times in a row and the mobs have either souls or dolls, its hc dont chance it just leave. if the mobs are soft fine ok do the baal run. dont get overly confident even with a hardened setup monsters can have a to hit deadly strike and it can do massive amounts of damage. i was on my din killing diablo and he had 9k life on him and diablo hit the char and did 3k damage from a single hit.