On Nightline Africa: U.S. Vice President Kamala Harris is set to start her three-nation visit to Africa this weekend where she will meet with Ghanaian President Nana Akufo-Addo, Tanzania’s Samia Suluhu Hassan, and Zambia’s Hakainde Hichilema. Plus, election observers in Nigeria’s recent gubernatorial elections express concern over widespread violence and voter irregularities. For this and more, stay tuned to Nightline Africa!