Preheat the oven to 400°F.
Wash and scrub the potatoes, then poke several holes in each potato with a fork.
Rub the potatoes with olive oil and sprinkle with salt.
Place them directly on the oven rack and bake for 45-60 minutes, or until tender.
While the potatoes are baking, heat a skillet over medium heat.
Add the ground beef and cook until browned, breaking it apart with a spatula.
Drain excess fat if necessary.
Stir in the taco seasoning, black beans, corn, and diced tomatoes.
Cook for an additional 5-7 minutes until heated through.
Season with salt and pepper to taste.
Once the potatoes are done, remove them from the oven and let them cool for a few minutes.
Cut each potato in half lengthwise and gently scoop out some of the flesh to create space for the filling.
Spoon the taco mixture into each potato half, then top with shredded cheddar cheese.
Return the stuffed potatoes to the oven for an additional 5-10 minutes, or until the cheese is melted.
Remove from the oven and top each potato with a dollop of sour cream, diced avocado, and chopped green onions.
Serve warm.