Prepare the Potatoes: Preheat the oven to 425°F. Line a rimmed baking sheet with aluminum foil.
Put the sweet potatoes on the prepared baking sheet and roast until fork-tender, 40 to 45 minutes. Remove from the oven.
Slice the potatoes lengthwise down the center and fluff the flesh with a fork. Work 1 teaspoon of the ghee and a pinch of salt and pepper into each potato.
Make the Chipotle-Lime Yogurt: Place the yogurt, chili powder and lime juice in a small bowl and stir to combine.
To serve, top each sweet potato with ¼ cup of the black beans, 1 tablespoon of the cubed avocado, 1½ teaspoons of the cilantro, ½ teaspoon of the chives, a drizzle of the chipotle-lime yogurt and freshly ground black pepper as desired.