Pour the peanut oil into a large (11 x 4-inch) stainless steel pot fitted with a candy thermometer; you want the oil to be at least 1-inch deep.
Heat the oil to about 380 degrees, or almost smoking.
Cut the tortillas in quarters (they will seem large) and add them in batches to the hot oil without crowding them. Cook for 2 to 3 minutes, turning once to brown evenly.
Remove the tortillas with a flat wire strainer or tongs and place them on a sheet pan lined with paper towels. Continue cooking the chips until they're all fried.
Meanwhile, combine the salt, chipotle powder, chili powder, and cumin in a small bowl. While the chips are still hot, sprinkle them evenly with the spice mixture.
