Preheat your oven to 375 F.
Scrub and pat potatoes dry. Pierce potatoes all over with a fork and bake in the oven, directly on rack, until soft (about 40 to 45 min. depending on the size of your potatoes).
In a bowl, combine all the ingredients for the taco seasoning.
Melt some cooking fat in a skillet over medium-high heat.
Add the onions and cook until soft and fragrant, about 3 to 4 minutes.
Add the ground beef to the skillet and cook until browned.
Sprinkle the taco seasoning onto the beef, and stir to combine. You may want to add 1 or 2 tbsp. of water if the meat is too dry or the seasoning is not mixing well.
Cook the ground beef another minute or two and set aside.
Using a sharp knife, make a lengthwise slit in each potato and push ends of each potato toward each other to open.
Fill the potatoes with the ground beef and top with all the remaining vegetables.
Serve with fresh homemade salsa.