They are definitely better than the Patriots at sacking the quarterback, and also worse at every other aspect of defense: worse on pass plays generally (even including sacks), worse at getting INTs, worse at run defense (where the Pats are also terrible but KC is absolutely brutal), worse on 3rd down, worse in the red zone.
Bob Sutton and Andy Reid have been there since 2013 and have had some very good defenses during that span (2014 & 2015 especially), so I don't think it's coaching / scheme. As for opponent, DVOA makes an opponent adjustment and the Chiefs only improve to 27th. I don't think this theory holds up to scrutiny, especially not when you consider some of the subpar defenses Belichick has deployed in the last decade.
A lot of folks saw this Chiefs D coming, too. Robert Mays was really down on them going into the year. USA Today
ranked them 29th going into the year.
Worth noting: the Chiefs pass defense is bad, but only like 10th-12th worst on a rate basis in most stats, but they face more passing attempts than any other team, probably because they lead so much. OTOH, their run D is awful, so getting to face more passes and fewer runs doesn't help them as much as it would most teams. Also,
the Chiefs defense has faced tied for the fewest drives of any defense in the NFL, and their opponents have the worst starting field position, so they are getting help from their offense in other ways and they are still terrible.