Cut the brisket into bite-sized cubes. Heat a tablespoon of oil in a large skillet and brown the brisket cubes in batches, being careful not to crowd them. As each batch browns, transfer them to the slow cooker. Replenish oil as needed while browning the meat.
Pour the chili sauce packet over the browned meat in the slow cooker, and add in as much of the spice packet as desired (1/4 packet for mild, or more to preference). Pour in a cup of red wine or water. Cover and set the slow cooker on high and cook for 5-6 hours, or until the meat is very tender.