Requesting, but not filing, a reply is not uncommon. If you’re totally fucked, a reply is just going to waste the judges time and make your arguments look worse.

So, the judge took the matter under advisement around 4pm on 9/6, according to one of the watchers on Xitter. (Cannot confirm the time this switched over to advisement but that’s when it was noticed). Under advisement means that the memos are all with the judge and we’re waiting for the judge to decide the issue. This status would not have been changed, barring some mistake from the clerk, if they were still waiting for the reply.
IMO Nicks lawyer / one of the paralegals called the court around 4pm and let them know that they
won’t be filing a reply, This is a common courtesy to the court, so nobody’s wondering if you missed your deadline / will be coming in hot with a
nunc pro tunc request for more time to file your reply one week later.
Now, to me, this seems like the most likely explanation. But I don’t know
how Nick’s lawyer convinced him they didn’t need a reply, but props to him for getting that through, I imagine that was a very uphill battle.