YMMV / Supernatural S 14 E 17 Game Night

• Informed Wrongness: Jack seemingly burning Nick to death may have been brutal, but the fact remains is that Nick had or attempted to murder several people throughout his rampage along with his pursuit to resurrect Lucifer. Which he almost succeeds, and that is after (as mentioned) him either murdering, seriously injuring, and causing distress to many, including innocents, along the way doing so. Not only does it prove the man to be an extremely dangerous fugitive but also a major liability, as he is (besides Sam) Lucifer's only suitable host. So if not for his soul, Jack could otherwise have chosen right to kill which would eliminate such a destructive liability otherwise.
  • The next episode addresses this, with Sam, Dean and Cas agreeing with Jack's decision to kill Nick, but taking issue with how he did it and considering it to be out-of-character for him, and thus a sign that he's soulless. It appears that this is Mary's opinion as well, since when Jack tells her that Nick deserved it, her response is "Not like this".