Star anise, anchovy paste, nutmeg, fennel, and barley are my guesses.
There is an America’s Test Kitchen Podcast called Proof that told this story. This was a VERY prestigious contest–invitation only. The guy’s two brothers received an invite. One of the brothers couldn’t make it so he gave the ticket to his brother. The brother just wanted the T-shirt that comes with turning in an entry. The result was the whole family was banned from the contest forever.
One of the points made in the episode was that this was proof of an old chili saying that the best chili is everyone’'s chili. Everyone makes chili they like, but the mixtures tend to balance out to a really good product that appeals to a broader audience.
I like this recipe from our very own Chefguy, who I hope won’t mind if I cut-in-paste it here:
Chicken and Black Bean Chili (by Chefguy)
This is a very flavorful and healthier version of the traditional Tex-Mex chili. You can make it with beef, but I prefer the lighter mouth-feel and taste of chicken. The spices are readily available at Penzeys or at any decent spice store. The amounts are a matter of personal taste, but don’t skimp. The chocolate in the dish gives it a mole’ flavor, which is common to many Mexican dishes.
3 boneless, skinless chicken breasts
1 large onion, chopped
1 green pepper, chopped
2 cloves of garlic, minced
2 jalapeño peppers, minced (optional)
Ancho chili powder
Cumin powder
Chipotle chili powder
Cinnamon
Mexican oregano, dried
Smoked Spanish paprika
Chocolate (60% cacao, minimum) - optional
Olive oil
3 cans black beans
1 can diced tomatoes
Salt, to taste
Cut the chicken into 1 inch pieces (easiest to do when partially frozen). Spread out on cutting board. Liberally sprinkle the ancho chili (at least three tablespoons) over chicken. Repeat with the cumin (at least two tablespoons), then lightly with the chipotle pepper (probably about two teaspoons or less; it’s hot). Add a liberal amount (several tablespoons) of Mexican (NOT Greek or Italian) oregano and a small pinch of cinnamon. Add a teaspoon or so of paprika. Toss the chicken until well coated with spices. Heat about ¼ cup (maybe less) of olive oil in a deep skillet over medium-high heat. Add the chicken and scrape in any leftover spices. Brown the spices well, turning the chicken frequently. This method releases the chile oils in the spices, making for a deeper flavor.
When the chicken is cooked and the spices browned, add the onions, peppers and garlic. Continue to sauté over medium heat. Open the tomatoes and drain the juice into a bowl. Chop the tomatoes until they’re at a size you like. When the onions and peppers are cooked, add the tomatoes and juice and the black beans. Bring to a boil and reduce heat to simmer. Add a couple of squares of the chocolate. Let simmer for about an hour or more.
To double this recipe, you really only need to double the amount of chicken, beans, tomatoes and garlic. The spices will adjust themselves as you dust the meat. You can eyeball the veggies to see if it needs more.
None of the guesses are right. But I’ve heard star anise gives it a pho sort of boost and might be worth trying.
No anchovies, but Worcestershire sauce is in there. I consider that a standard ingredient, though. I don’t think it would be very easy to guess my additions, but probably some of them have been tried before.
I’ve thought of another few additions that might be worth a try. These are not in my original recipe. The stuff I just thought of include grape jam (since a party dish of meatballs glazed in a mixture of grape jam and chili sauce is surprisingly awesome), coffee cream (sometimes used in meatloaf or a good Bolognese) or epazote (a Mexican spice not widely available in Canada). But my additions make more sense. They might even have commercial value. I’d tell Jnglmassiv, but his secret ingredient might turn out to be Pop Rocks. 
My non-standard ingredients are anchovies and Dona Maria mole paste.
I dunno. Coffee? Whiskey? Some kind of jam or jelly? Cola? Chocolate (though that, like coffee, is fairly well known). Tamarind paste? Shrimp paste? Fish sauce? ETA: oh, I see you’ve mentioned jam/jelly possibly for your next iteration. I would say no to epazote. Have you had it before? I don’t think it would go well with chili.
I don’t consider Worcestershire standard in chili. Other stews, yes. Chili? No.
Chili does not have beans in it. You can include beans, but it is then referred to as chili with beans.. I prefer are a mixture of beef, pork and lamb as the base for my chili.
I do not have a specific recipe but a general base that I start with. I then add various spices and chiles for taste, over time. I normally cook my chili over a 5-6 hour time.
Undercook the onions?
None of those guesses are right. I’ve never tried epazote with chili and don’t know if it would go. Maybe Mexican pepperleaf would.
It does have cocoa, but no other chocolate flavour. Again, so do many good chilies and the very good Cook’s Illustrated recipe. I don’t subscribe, but have many back issues. I don’t know if this can be accessed without leaving information.
Many chili purists don’t like adding beans or sometimes onion or tomato. I don’t disagree, exactly, but I’d rather make a healthy chili than a pure one. I think all those additions boost the flavour and nutrition.
I’ll share one my secrets.
Baby onions. You can sometimes find them frozen. You could use boiling onions, but they are so tedious to peel! The best substitute would be the Mexican green onions. They are like scallions, but have a bulb at the root end. Try to get the smallest ones you can.
Under no circumstances are you to use a jar of pickled onions, like the ones that go into martinis!
You serve up a pot of chili with little onions, and people are delighted!
You’ll still need chopped onions to cook down in the chili, because the whole little onions are a last-minute addition.
~VOW
Not a bad idea, serving chili with finishers: lime crema, cumin crema, green onions or real Parmesan cheese.
I use a lot of scallions. But my chili uses red onions, they cook for a long time.
I like Melba toasts with chili too.
Oh, god, so sick of 20-plus years of chili threads.
Look, just keep cooking chili until you’ve arrived at your very own perfect bowl of red. Then tell everyone else to fuck off, because yours is the best. That’s what I do.
Likewise, I’m sure. I have a problem with folks asking others about secret techniques while maintaining their own. That’s especially true with the ridiculous notion that there’s any money to be made with a chili recipe.
This. And I add some chorizo to the chuck
I didn’t ask anyone for secret techniques, just general opinions. Chili may be a timeworn and tiresome topic, so skip the thread. No recent threads on red chili, and I have no interest in the green stuff. But when you’re bored with chili, you’re bored with life. Or not.
Like anything vaguely competitive, people take it too seriously. Sure, I’m in danger of doing the same. But the thread is meant to be lighthearted. There are many threads on repetitive topics. Not all of them are healthy and delicious.
I’ll sell you my secret recipe for $50,000. 
:D:D:D
I apologize for being the party-pooper.
And my check is in the mail.
I’d think my dentist might know a thing or two about chili (he’s a 2 time Terlingua cookoff champion)… His recipe is pretty simple overall, but it’s really good.
I’d say that the best thing you could do overall to improve your chili would be to improve the quality of your chili powder or powdered chiles. Penderys and Mild Bill’s are both good places to order from in that regard.
[Moderating]
But not, apparently, sick enough of them to stop you from opening this one. Were it not for the fact that you’d already apologized by the time I saw this, this would have been a Warning for threadshitting.