Much more cheese.
Oh, and onions are part of the charm.
No real offense but: Cincinnati chili is NOT chili and Skyline Cincinnati chili, whether it be 3 way, four way or five way has to be one of the worst things I have ever eaten!
Please note that coming from New England where Haute Cuisine is Boiled New England Dinner (just take cabbage, cheap ham, potatoes, turnips, and whatever other root vegetable is available, and boil everything until it is an inedible soggy, mushy mass of horridness) I've had plenty of weird and completely unappetizing foods. We need White Castle up north too!
If anyone must replicate Skyline Cincinnati chili but can’t travel to Cinn: buy the cheapest and worst canned chili (without beans) you can find, heat it up and toss it on some thin spaghetti pasta, and then cover it with shredded supermarket brand American cheese and you have a close approximation (but possibly not quite as bad). You really need beer with this “meal” but I don’t think I’ve ever seen any beer other than Bud, Bud Light, Miller, etc at the places where they sell this concoction.