Wrap potatoes in foil and place in 350 degrees F oven for about 1 hour. When potatoes have 20 minutes remaining, brown ground beef. Add 1/3 cup of water and taco seasoning to ground beef. Simmer for 10 minutes.
Cut potatoes in halves and scoop out middle to make "taco" shell. Add meat, sprinkle cheese on top. Place back in oven for about 5 minutes or cheese melt.