It's been decades since FUD so obviously there were tons of other valorous soldiers he met (Corporal Harland, Corporal Locklear, Johnson). Not to mention, Lasky grew up. By the time of Halo 4, he is easily in his late 30s/early40s.
Some people think that lasky asking chief if he has any experience clearing landing zones and chiefs 'on occasion' reply is a nod towards the events of FUD.
Lasky gave a wink and smiled and Chief gave a nod, I don't see how it could be interpreted any other way. Nodding and giving a one-liner is already exploding the boundaries of how familiar the Chief gets normally.
What y'all need to understand is that Chief has a good memory, he's just not particularly sociable. He obviously remembers Lasky, and even if he didn't Lasky reminds him they've met before twice in the game, once in the bunker on Requiem, "Never thought I'd see you again." and once on the Infinity after defeating the Didact "it feels kind of odd for you to call me sir". Do you really think a Spartan is going to forget any of their campaigns? Hell no, they retain all that for tactical reference.
So Chief obviously remembers Lasky. But what did you expect him to do? Give him a pat on the back and say how great it is to see him again? No. He's the goddamn Master Chief. He's a huge, awkward manly-man. He doesn't even know how to respond to Lasky being all chummy with him. He just doesn't know. So he just stands there awkwardly and lets Lasky continue talking since Lasky is in charge.
Is there something about the way I type that makes it sound angry? Maybe it's just something about the way you read.