Lightly oil the bottom of a large dutch oven, to prevent the nachos from sticking.
For the first layer, evenly spread 1/3 of the chips into the dutch oven, topped with 1/4 can El Pato, 1/4 can black beans, 1/4 cup cheese, and a handful of avocado and green onions. Repeat for the second layer.
For the third, and final layer, use the remaining 1/3 portion of chips, 1/2 can El Pato, 1/2 can black beans, 1/2 cup cheese, and remaining avocado and green onions.
Cover the dutch oven and place on a metal grill over your campfire for about 10 minutes, until the cheese has melted. Serve with the lime wedges.