Can you explain how the creditors of 4bn in Neiman Marcus debt are making money off this?

Because they won’t default now.

Ok, a potential positive sum is definitely better than zero but once again, how exactly are creditors making money off this? The grandparent's post is implying that somehow no one is losing money in this situation. I'd like to hear how it works.

They probably sold the debt to another party

So you're saying that the original creditors made money off this and new creditors through secondary market transactions are left holding the bag? That's partially true but a massive portion of this debt is in pension funds or passive investments that track index funds. They track benchmark indices so they're buying these bonds at issue or shortly after. With no active management involved, they are also losing money when a company files.

The creditors definitely won't make money.

They are other banks, and probably all the suppliers who give to NM on credit and who won't get paid.

Chapter 11 is by default bad news for creditors, it means they will get less than the agreed-to value of whatever.

They're not making any money, but they're not universally worse off.

Depending on their status (e.g. if their debt is secured by a lien), it's totally possible that some classes of creditors could be reinstated with the same claims under the reorganization plan (assuming it gets confirmed by the court). Even if a secured class doesn't get the same value and votes against the plan, they're still entitled to a handful of protections under the Bankruptcy Code (§ 1129(b)(2)(A)). Less so for unsecured creditors and shareholders.