he's right there. he at least seems to not be paying attention. we don't see much, but just enough to know he may or may not notice. nacho's aware. he thinks dude is distracted and not looking, but nacho's kind of looking back at him being obvious. the guy easily has enough time to look away and pretend he doesn't notice nacho, but we don't know because we're not seeing him.

then we don't even know if he'd drop dime to don hector, extort nacho for money, mind his own business. hector thanks him and kills him for snitching. or he didn't see shit, and it's not any kind of issue. so many possibilities from that one thing.