Apparently, chain devils were important enough to get their own picture. I don't mind: they're one of my favorite kinds of devil. Interestingly, they're not Baatezu.
What are their racial traits? First of all, 8 outsider HD. Chain devils are slow by diabolic standards, with only 30 feet movement. Their stats aren't very impressive: even the lower-ranking bearded devils get (slightly) better ability scores. They're merely medium-sized, but at least they get reach with their natural weapons.
Chain devils have a few unique abilities. Unnerving gaze isn't that great (at least it takes no action), but Dancing Chains is a flavorful way to add a few attacks to your repertoire. Depending on whether they inherit all of your attack boosters (precision damage, magical buffs), this is either decent or absolutely wonderful.
Another notable trait is regeneration. It's only overcome by silvered or good-aligned sources of damage: things your average monster probably won't have.
All in all, I don't think chain devils deserve a LA. While they undeniably possess defensive strength, their damage output is just too low. Compare a chain devil with 12 rogue levels (+6d6 sneak attack damage) who gets six attacks per round to a 20th-level rogue who gets four attacks with +10d6 points of damage on each. And that's assuming the chain devil can add precision damage to his dancing chains which, as said before, is debatable.
+0 LA, but anyone is welcome to challenge this.