In English, Nick's word choice right there has a strong Biblical resonance. Maybe you might enjoy comparing the usual German of that Biblical passage to the German translation of Nick's line?

In the "Dark Knight, the Second Chapter" flashback, in English, Nick says, "I shall repay you." (Later, the same flashback is re-used in the episode titled "I Will Repay.")

New American Bible (translation c.1990):

• Leviticus (3 Mose, Levitikus) 32:41: "With vengeance I will repay my foes and requite those who hate me."
• Romans (Römer) 12:19: "Beloved, do not look for revenge but leave room for wrath; for it is written, 'Vengeance is mine, I will repay,' says the Lord."

King James Bible (1604-1611, most influential English translation in history):

• Leviticus (3 Mose, Levitikus) 32:41: "I will render vengeance to mine enemies, and will reward them that hate me."
• Romans (Römer) 12:19: "Dearly beloved, avenge not yourselves, but rather give place unto wrath: for it is written, 'Vengeance is mine; I will repay,' saith the Lord."