Place the olive oil in a 4-quart pot and preheat over medium-low heat. Add the onions and garlic, and sauté for 2 to 3 minutes, or until the onions are translucent and the garlic is lightly brown.
Add the bell peppers, carrots, and squash to the pot, and continue to sauté for 5 to 10 minutes.
Stir in the remaining ingredients. Simmer covered, stirring frequently, for about 2 hours, or until the liquid is somewhat reduced and the chili is thick.