In bowl, microwave sweet potato with 3/4 cup water, covered, on high, until tender, about 10 minutes. Drain. In nonstick skillet, cook chorizo over medium-high until browned and crumbled, 8 minutes. Add eggs, tomatoes, cheese, sweet potato and half the cilantro; season. Cook, stirring, until eggs are just set, 5 to 7 minutes. Top with sour cream and remaining cilantro.