The best way to get Torvald down is the combo between Wrecker and Street Justice. Keep your distance if you know Nullify is up, because Nullify is your ruin. Knock his health down from a distance, rush in, and pounce once hes at/below half health.
When Torvald ULTs, you can use Pounce to reverse the knockback, saving you from falling into the pit and gain a ridiculous speed needed to get back to safety.