Nils Andersen, the former chief executive officer of the shipping company, A.P. Moller Maersk, has been named the chairman of Unilever’s board of directors, effective immediately. Mr. Andersen replaces Marijn Dekkers, who led Unilever’s board for three-plus years. Mr. Dekkers, who will remain on Unilever’s board, is leaving to concentrate on Novalis LifeSciences, an investment and advisory firm he founded in 2017.