1. In a large saucepan, heat oil over medium heat. Add the onion and garlic and sautee for about 5 minutes until onion is translucent.
2. Add the bell pepper, jalapeno (if using), sweet potato, and tomatoes with their juices. Raise the heat to medium-high and simmer for 5 minutes. Season with salt and pepper.
3. In a medium bowl, whisk together almond butter and 1 cup of the vegetable broth until no clumps remain. Stir the mixture into the saucepan of vegetables along with the remaining 3 cups of broth, chili powder and the cayenne pepper (if using).
4. Bring to boil then add chicken.
5. Reduce heat and simmer for 15-20 minutes until sweet potato is fork tender and chicken is cooked throughout.
6. Toss in spinach or kale and cook until wilted. Season with salt and pepper to taste and serve with cilantro if desired.