Mix taco seasoning in a small bowl. Brush both sides of potatoes with oil, place potatoes face-down on lined baking tray, and sprinkle with seasoning mix. Bake for about 10 minutes until skins start to crisp then remove pan from oven, flip them over onto their backs and fill each skin with tomatoes, corn, black beans, jalapeƱos, and additional taco seasoning. Bake for another 10 minutes until edges are crisp.