On a side note: Peanuts are also very common in authentic mole sauces, and sometimes enchilada sauce, which is why I always make my Mexican sauces at home. And peanut butter is often used in chili, as well. We are very careful about the Mexican food we eat out. Always ask for an allergen menu if you are allergic.
The primary spices in this chili are allspice, coriander, and a basic red chili powder - all common to central Mexico. The chocolate fits seamlessly into the blend and adds a luscious, slightly bitter mouth feel. (I use unsweetened Baker's Chocolate from Canada which is safe for those with peanut allergies.) To balance the bitterness I add a handful of raisins, chopped very fine. The combination is perfect. This dish is all about layers upon layers of complex flavours simmered together slowly. I made this batch in the slow cooker, but it can just as easily be made in a heavy pot on the stove top. Serve with warm skillet corn bread, traditional Mexican-style tortilla chips, or a rolled flour tortilla. Top with crumbled queso fresco.