Preheat oven to 400 degrees F (200 C). Scrub potatoes and dry then pierce with knife in a few places and wrap in aluminum foil. Bake for 45 minutes to 1 hour or until soft when squeezed. Remove from oven and allow them to cool enough to handle. Cut them in half lengthwise and use a spoon to scoop out center leaving a little bit of flesh. (You can make mashed potatoes with the rest, Yay!)

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, jalapeños, and additional taco seasoning. Bake for another 10 minutes until edges are crisp.

Remove from oven and cool for about 5 minutes, then top with guacamole if desired and serve warm.