In a mixing bowl, combine heavy cream, evaporated milk and salt. With a stand mixer, beat until stiff peaks form gradually increasing speed to high, as mixture thickens. Slowly drizzle in sweetened condensed milk starting mixer speed at low and gradually increasing it to high. Beat on high speed until stiff peaks form. Add vanilla extract. Beat until it is well blended, maintaining stiff peaks. Spread one-third of the ice cream onto the bottom of a freezer-safe container. Spread half of the fudge swirl over ice cream. Spread one-third of the ice cream over the fudge swirl. Spread half of the fudge swirl over ice cream. Spread remaining one-third ice cream over the fudge swirl. With a knife, gently swirl the ice cream with the fudge swirl back and forth about two times. Cover tightly. Freeze until firm and completely solid, about 8-10 hours.
Place heavy whipping cream and semisweet chocolate chips in a double-boiler. Stir until all of the chocolate chips have melted and the mixture is smooth. Cool completely. Store in a tightly covered container in the refrigerator.