For those who are interested, Warpriest armor (helm, body, bottoms, gloves and boots) works to keep Nex from melee-distancing you repeatedly on smoke and shadow phases, and overall offers about half the damage reduction as tank armor would, at the advantage of offering full weapon accuracy without armor switches
I say half because a set of tank armor provides a flat damage reduction of around 9%, where 5 pieces of Sara/Zammy warpriest is a 5% chance of a 90% reduction, which works out to a 4.5% damage reduction
That's mainly for the tank though, as the tank is the only one in danger of the melee chasing. Damagers could likely wear warpriest gloves and boots to avoid penalty in one combat style, along with a helm just because, and wear power armor for the increased damage