Heat oil in heavy Dutch oven. Add onion, garlic, and jalapeño. Sauté until tender. Add chili powder and cumin, to taste. (Add cayenne if you want it spicier and hotter.) Cook and stir 1 minute. Stir in beans, tomatoes, water and sugar. Bring to a boil. Reduce heat and simmer 20 minutes or until thickened. Season with salt and pepper. Adjust spices to your taste. Add chicken broth or water to make thinner. Serve over tortilla chips and garnish with sour cream and cilantro.