Lvl 160 Nova here… she can soak… just badly. Virtually any hero is better at soaking and hence it should be you and not her who is doing it. If it is QM and the enemy team comp is really bad a.k.a full of warriors with large HP pool or your team si bad and hence the oportunity for ganking is low, then she can roleplay laner because it is better than nothing but it is still better to use her as a mage and poke than laning.
It doesn’t mean she cant prevent siege damage by enemy wave if needed. All it takes is make sure that your side has more minions than theirs, she doesn’t have to kill the entire wave. Just make sure her wave will not loose and off she goes do some hero damage somewhere else.