Pierce the sweet potatoes several times with a fork and wrap in aluminum foil. Bake for 45-60 minutes or until tender.
In a medium skillet, heat the olive oil over medium heat. Add the garlic and cook until fragrant, about 30 seconds.
Add the black beans, cumin, chili powder, smoked paprika, oregano, thyme, salt, and pepper to the skillet. Cook until heated through, about 5 minutes.
Remove the sweet potatoes from the oven and let cool for 5 minutes. Cut each sweet potato in half lengthwise and scoop out the flesh into a large bowl.
Mash the sweet potato flesh with a fork or potato masher. Add the lime juice, cilantro, and black bean mixture to the bowl and stir to combine.
Fill the sweet potato skins with the mixture and place back on the baking sheet.
Sprinkle shredded cheese over the top of each filled sweet potato.
Bake for 10-15 minutes or until the cheese is melted and bubbly.
Serve each sweet potato topped with diced avocado and a dollop of sour cream. Enjoy!