Don't forget, Gus knows that Nacho previously asked Mike to kill Tuco, and then subsequently poisoned Hector. So in Gus' eyes Nacho has a thing about trying to murder his bosses.

Gus would not threaten Mike. At least not at this point. It was all about Nacho.


>But why would he say that about nacho?
>
>Nacho wasn’t being feed or worked for him. He was being
>forced and threatened, where he had no choice. His father’s
>life was on the line.
>
>When Mike asked him, Gus said no, he could still be of some
>use to us. Mike put seriousness in his tone and asked him
>again, and questioned the purpose of it. Gus paused, stared at
>him and then said that.
>
>Maybe it did relate to nacho, but somewhat directed to Mike as
>well.