Preheat the oven to 325 degrees F (165 degrees C).
Beat egg whites with salt in a bowl until frothy; add sugar gradually, beating to stiff peaks. Gently fold in pecans, almonds, and cinnamon. Pour mixture onto a 15 1/2 x 10 1/2-inch jelly roll pan, drizzle melted butter over top, and toss to coat.
Bake in the preheated oven, tossing every 10 minutes, until nuts are crisp, about 40 minutes. Serve warm or at room temperature.