Heat skillet over medium heat. Once hot, saute onions until translucent and soft, 5 - 7 minutes. Set aside.
Mash the dried and drained beans in a large bowl with only a few chunks remaining.
In a food processor or blender, add nuts, spices, salt and pepper to taste. Pulse until a fine meal is achieved.
Next, add cooked rice, spiced nut mixture, sauteed onion, panko bread crumbs, chopped hatch chili pepper and BBQ sauce to the bowl of mashed beans. Mix thoroughly to form a moldable dough.
Shape veggie burger mixture into eight patties. Place a chunk of sharp cheddar in the middle of four patties. Top with remaining patties and seal edges together.
Grill the patties over medium heat for 3-4 minutes on each side. Serve with toasted buns, tomatoes, ketchup, avocado, and anything else you can think of.