Heat a large, nonstick skillet over medium-high heat with oil, 1 turn of the pan. Add beef and brown and crumble. To browned meat, add onion, garlic, chilies, garlic, spices, salt and pepper. Stir to toast spices then add stock to pan and simmer to thicken.
Cut the top third off the potatoes and scoop the potato flesh into a bowl. Arrange the potato shells on baking sheet. Mash potato flesh with half the beef and cheese, and stuff potato shells. Top with crushed tortilla chips, remaining beef and cheese—it should look like nachos on a potato—and bake or broil until lightly browned and bubbly.
Top with lettuce, tomatoes, onions, sour cream, avocado and pickled jalapeño pepper slices.