Gather all equipment and ingredients.
Heat large stock pot on medium-high. Add oil. Add onion, sauté until fragrant and translucent, approximately 3–4 minutes. Add the sweet potatoes, stirring occasionally, and sauté for 5 minutes.
Add peppers and garlic. Sauté for about 5–10 additional minutes, or until mixture is fragrant and potatoes are fork tender.
Stir black beans, kidney beans, tomatoes, tomato sauce, jalapeño, cumin, and chili powder into the pot. Add more tomato sauce if mixture is too thick.
Bring mixture to a simmer. Reduce heat, stirring occasionally until chili is thoroughly heated through.
Taste and season with salt and pepper and serve warm.