An easy way to thicken chili is to add a creamy ingredient like cream cheese or for a leaner version, Greek yogurt. Additionally, you can blend a few cups of the chili into a smooth consistency and stir it back into the soup. Another easy way to thicken chili is by adding a little bit of cornstarch as a thickening agent. Make a slurry by mixing one tablespoon of cold water with cornstarch and add it to the chili. Keep in mind, this will increase the carb count.