In a food processor, add the walnuts, onion, cilantro, garlic, cumin, oregano, and basil. Pulse until just combined and add the black beans and green chile peppers. Pulse until just combined.
Transfer the mixture to a large bowl and add the eggs, nut meal, and black pepper. Using damp hands, shape the mixture into six (3/4-inch-thick) patties. Place the patties on a baking sheet, cover, and chill until ready to grill up to overnight.
Preheat a grill to medium heat and grill until cooked through and lightly golden, turning halfway through, about 10 minutes in total.