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).
If Barik is running One Man's Scrap on a high level try to use CC (To prevent Barik destroying them himself) and avoid the turrets to prevent this form of healing.
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.