Step 1: In a small bowl, combine the sweetened condensed milk, instant espresso powder, vanilla extract, and sea salt. Stir vigorously until the espresso powder is completely dissolved and the mixture is smooth.
Step 2: In a large chilled mixing bowl, beat the cold heavy whipping cream on medium-high speed until stiff peaks form. Be careful not to overbeat into butter, but the peaks should be firm enough to hold their shape.
Step 3: Gently pour the coffee and condensed milk mixture into the whipped cream. Using a rubber spatula, use a folding motion to combine the two. Do this slowly to keep the air in the cream, which is vital for the texture of the no churn coffee ice cream with chocolate chunks.
Step 4: Once the mixture is mostly streak-free, fold in the chopped dark chocolate chunks until evenly distributed.
Step 5: Transfer the mixture into an airtight container or a loaf pan. Smooth the top with a spatula and sprinkle a few extra chocolate chunks on top if desired.
Step 6: Cover tightly with plastic wrap or a lid and freeze for at least 6 hours, or ideally overnight, until firm.