Put the chipotles, tomatoes, and 1½ cups (360 ml) water in the slow cooker and use an immersion blender to puree the mixture until smooth (or puree in a blender and transfer to the cooker). Add the chickpeas and sweet and russet potatoes. Cover and cook on low for 8 hours.
Morning or Evening
In a small bowl, whisk together the peanut butter, lime juice, and about 6 tablespoons (90 ml) water, or enough to make a pourable sauce. Season with salt. Cover and refrigerate if doing this in the morning, then bring to room temperature or warm in a small pan or the microwave oven before serving.
Stir the cilantro into the stew and season with salt, if needed. Serve the stew with the peanut sauce for drizzling.