In the same skillet, with the rendered bacon fat, add the onion and sauté about 5 minutes until soft. Add in the chopped poblano and minced garlic and cook for 5 minutes and 30 seconds longer.
Mix in the salt, brown sugar, and brisket rub. Deglaze the pan with a splash of beer if needed by adding the liquid to the pan and scraping up any browned bits.
Add the barbecue sauce, ketchup, mustard, and Worcestershire and stir to combine. Add the beans and allow the dish to smoke over the grill about 45 minutes.