Nullify makes BK completely useless. For talents if you know the how good the enemy BK is (from previous matches), BK is the only dmg or your other talents would be useless in the match pick the Direct Current talent to make it harder for BK.
If a Torvald is looking at one of their allies, they are probably going to give them a shield, take advantage of this moment via moves that require Torvald's attention to dodge (e.g Makoa hook, Damba reload etc).
When playing against a strix as sha lijn strix will be a better long range duelant. Try to hide behind rocks a peak out on different spots For Some free damage.
Your ult is extremely important. you need to do dmg to get it quickly. moral boost and generalized vollys of weapon dmg into the frontline when not in active combat should bring your ult to use very quickly