Though not quite on the scale of Rochester’s Destination Medical Center project, Duluth’s two health providers are in the midst of major expansions. Essentia Health’s $800 million Vision Northland project, which will add 928,000 square feet of hospital space, will transform Duluth’s skyline. Though more modest, St. Luke’s $37.5 million project will allow the smaller of Duluth’s top health providers to stay competitive. Keeping up with Essentia is just one of the major challenges facing Kevin Nokels, who became St. Luke’s chief executive in August. The Minnesota native left the presidency of Creighton University Medical Center in Omaha to succeed John Strange, St. Luke’s president and CEO for nearly 23 years.