Heat olive oil over medium-high heat in a Dutch oven or heavy-bottomed pot. Once hot, add the peppers, onion, and garlic; saute until the onions are translucent, about 6-8 minutes.
Add remaining ingredients and stir well to combine. Bring to a boil and reduce heat to a simmer.
Simmer over low heat for 2 to 2½ hours, stirring occasionally.
Serve garnished with sour cream and grated Cheddar cheese, if desired.
Notes
Adapted from "Three-Bean Chili, Veggie Option," The American Cookbook, Caroline Bretherton & Elena Rosemond-Hoerr, submitted by Lynn Jackson