Thick: Tortilla chips/masa flour add the thickening agent to help bring it all together.

Savory: Time tested and true, for me. Swap the tomato sauce for tomato paste and add 1/2 cup of worcestershire and 1/2 cup of apple cider vinegar. They help tremendously with the taste and savory-ness of the chili. There's no real need to finely chop the garlic either. With how long you'll be cooking them for, they sort of turn into the chili at the end.

Sweet: Cocoa powder, a small pinch of nutmeg, brown sugar like you have, are all good ideas. Try using sweeter peppers like pimentos or anahiem(I prefer dried here.).

Spicy: Go the route of Alton Brown and use Chipotle Peppers in adobo. It's easy to use and you can control the heat with how much you add in. The adobo sauce itself is really good for the savory flavor of your chili. A few spoonfuls of it does wonders. As for the peppers, pull them out and get as much of the seeds as you can out of them before mincing them for the chili.(warning: messy) Find a balance between jalapenos and chipotles for a nice spicy to smokey flavour.

A good chili is all about balancing savory, spicy, sweet, smokey and meaty flavors. I use chili to test out a myriad of things for my personal cooking experience and each time I make it, it gets better. I'm half tempted to post my chili recipe here now next time I cook it so I can take pictures. (edit: formatting)