Start by lining a cookie sheet with a silicone baking mat or parchment paper.
In a microwave-safe bowl, add the dark chocolate or bittersweet chocolate chips. Heat in the microwave in 30-second intervals, stirring in between, until the chocolate is fully melted and smooth.
Once the chocolate is melted, add in the roasted almonds and pistachios. Stir until all the nuts are well coated in the chocolate mixture.
Using a spoon or spatula, scoop out small amounts of the nut and chocolate mixture onto the prepared cookie sheet, aiming for clusters that are about 1 to 2 inches in size.
Before the chocolate sets, sprinkle a little kosher or sea salt over the top of each cluster.
Allow the clusters to cool at room temperature until the chocolate is set or pop them in the refrigerator for about 15-20 minutes if you're in a hurry.
