Preheat oven to 350°. Spread pine nuts on a rimmed baking sheet and toast until golden brown, about 5 minutes. Set aside to cool.

Heat the butter in a large, ovenproof skillet over medium-high heat. Reduce heat to medium, add onion, and cook until soft, about 5 minutes. Add the sweet potatoes, chili powder, cumin, and1/2 teaspoon salt. Cook until sweet potatoes are tender, about 5 minutes.

While the sweet potatoes are cooking, add the pine nuts, sour cream, and cilantro to a blender or food processor and puree until smooth.

Add the puree, rice, chicken, black beans, chiles, hot sauce, and salt to taste to the sweet potatoes in the skillet and mix well. Sprinkle the cheese on top. Bake for 30 minutes, or until bubbly and golden brown. Garnish with cilantro.