Minus 30 is very cold for bees. Some people do use insulating board & in Europe there is a type of hive that is made basically like an ice chest. Made of styrofoam or something like that.
I think the chips are probably helpful unless they attract pests or absorb water. What I would probably do is sandwich the nuc between the other 2 hives & surround them all with hay bales. Top and sides. Keep their entrances open. That works pretty good. Don't know how well that works in minus 30 though. That's harsh.