Pre-heat the oven to 400 degrees and line a baking sheet with foil.
Use a fork to poke several holes on one side of each sweet potato. Place the potatoes on the baking sheet hole-side up.
Drizzle the potatoes with 1 tbsp olive oil and sprinkle with salt then bake for about 1 hour.
While the potatoes bake, place the beans and the corn in a bowl. Add the remaining olive oil and the taco seasoning. Toss gently until beans and corn are coated. Set aside.
When the sweet potatoes can be easily pierced with a fork, remove from oven and cool for 5 minutes.
To assemble, slice the sweet potatoes open and use a fork to mash the inside slightly.
Spoon beans into each potato. Add the chopped tomatoes and avocadoes, then top with cheddar, sour cream and cilantro. Serve immediately.