No flight suits in the NCR isn't new, and isn't from CNO. In fact, they just changed the NCR uniform policy to allow Type IIIs instead of khakis. I'd personally rather where khakis than guacamoles.
I've avoided the "building" or any job in DC, but I'm fairly certain flight suits in NCR have been restricted to personnel flying that day for at least 10 years.
So...other than a brief period 2019-2020ish, when type III NWUs were allowed in the Pentagon, Pentagon has been khakis or higher. I think we're on the same page with this.
Outside of the Pentagon but at other NCR Navy commands, NWUs seemed like a "local guidance"-type thing, and the instruction, as related to me when I checked in at my WNY command, was that wherever NWUs could be worn, flight suits could also be worn.
You're right, the instruction two weeks ago was released by N1, not acting CNO. Complete coincidence. Before that instruction I was wearing my flight suit. After, I am not. And the instruction specifically bans flight suits (tradeoff for NWUs, I guess), and there would be no point in that unless they were authorized.