Heat oil in a medium saucepan and sauté the onion and garlic for 2 to 3 minutes. Add the celery and mushrooms and sauté another 2 to 3 minutes. Add the chili beans and kidney beans, cocoa, cinnamon, and 1/2 tsp sea salt. Bring to a boil, reduce heat to medium-low and simmer for 15 minutes.
While the chili is cooking, prepare the tofu sour cream by placing all ingredients in a blender and blend until smooth and creamy.
Preheat the oven to 350° F. Heat taco shells for 3 to 4 minutes. Remove, fill each taco shell with lettuce, chili, tomatoes and avocado slices. Top with tofu sour cream.
Per serving - 294 calories, 9 g fat (28% calories from fat), 15 g protein, 39 g carbohydrate, 13 g fiber, 0 mg cholesterol, 622 mg sodium