Nationstar Mortgage | 33,860 followers on LinkedIn. Nationstar Mortgage is a recognized leader in the mortgage industry with more than two decades of experience, and its flagship brand, Mr. Cooper, is the largest non-bank mortgage servicer in the nation. Nationstar Mortgage serves customers at every point of the home loan journey, with a focus on delivering a variety of servicing and lending products and technologies to make the home loan process more rewarding and less worrisome.