So, Nacho is pretty reserved and likes to wait until the right moment to act... I think it's maybe entirely possible that he either saw the network post or was in the Crossing when Strange attacked the back gate (far enough away to not get seriously hurt by it but close enough to see at least some of what happened) but didn't say/do anything at the time because 1.) what exactly was he even gonna do anyway lol, and 2.) wanting more info. But maybe he approaches Strange to talk about it later on when things are quieter? If you think that'd work! If not, happy to brainstorm something else.