Preheat outdoor grill to medium-high or oven (if cooking indoors) to 350 degrees F.
Cut 8 large pieces (about 14-16" long each) of foil and lay two pieces on top of each other in perpendicular stacks (to form sort of a plus sign shape) to start 4 grill packets. At this point, you can line them with parchment paper if desired. Simply lay a single piece just on top of the top piece of foil.
Heat the oil in a large skillet over medium heat. Add the onion and cook until soft but not browned, 3 to 4 minutes.
Add the ground pork (or beef) and cook while breaking up the meat with a spatula. Continue to cook until the meat has browned all the way through. Drain off the fat (if desired), then season with chili powder, cumin, oregano, and salt. Stir in the lime juice and set aside.
Evenly distribute the chips on top of the foil pieces then top with equal amounts of cooked meat and grated cheese. Try to cover as many chips as you can with the toppings!
Carefully bring together the two ends of the foil from the bottom piece so that the edges meet at the center. Fold the two edges together over at least three times. Then, rotate and fold up the edges on the open sides at least two to three times and crimp those together with your fingers as well (see video demo below). Punch some holes in the top to help prevent the chips from getting soggy.
Place the packets on the grill or in the oven and cook until the cheese is melted, about 10 to 12 minutes. Carefully open packets, add additional desired toppings, and serve!