If chili is too hot, and you have room in the pot, this is a time to ignore the beans/no beans Great Chili Divide and add a can of beans. Beans dilute the heat. I'm in the "no beans" chili camp, but if I had company coming and had accidentally dumped in a whole bottle of one of the hot elements...you bet I'd add beans. The beans will need some simmering time to do their best, so simmer another 20-30 minutes. Eat a bean and see what you think.
A big handful of saltine crackers crushed and stirred into the chili will also tame a moderately too-hot chili (and definitely will tame one that's just a tiny bit more than you wanted. Bread does not work as well as crackers.
If you don't have room in the pot, or don't want to add beans, I just discovered two new ways to use chili that may help. with either leftovers or too-hot chili.
1. Baked potato and chili. Bake your russet potato while warming the chili and grating/shaving/dicing some cheese. When the potato is nicely baked through, split and break up the interior a little. Now add chili, put your cheese on top, and stir potato, chili, and cheese. A dollop of ranch dressing (and I suppose sour cream or crema would work as well) also takes the heat out and tastes really good with the potato. I had this for supper last night, and not because the chili was too hot--we didn't have enough chili left. But I noticed the chili didn't have any bite left. (You can also--if you have boiling potatoes and not baking potatoes--boil up some potatoes, break them up with a fork, and put the chili and cheese and whatever else over them in a bowl.)
2. Cornish pasty-inspired chili pasty. I had some leftover pie dough, still flexible...so I spooned some chili (maybe 4-5 tablespoons?) and some grated cheese onto one half of a sort-of-circle of pastry, folded it over, made the twist closure, and put it in a 350F oven. This time I used the last spoonfuls of cold chili so I could clean the pot for the next batch and it wouldn't be cluttering the fridge.
If chili isn't hot enough, that's the simplest to fix. Gauge the amount of "not hot enough" that's in it, and add (in increments...once it gets closer to "enough" it's easy to go over the line to "too much") any of the relevant peppers whose flavor you like. I've used a bit of cayenne, or jalapeno, or Serrano. If you don't have good fresh peppers available, dried will do, and so will canned.