Soak cashews in a bowl with water to cover, 3 hours to overnight; drain.
Mix almonds, pecans, dates, 2 teaspoons coconut oil, cocoa powder, and salt together in the bowl of a food processor until finely ground and beginning to form a paste, 1 to 3 minutes. Press mixture into the bottom of a 9-inch springform pan. Refrigerate crust until ready to use.
Process cashews in the bowl of a food processor until finely ground. Add banana, cinnamon, nutmeg, and vanilla extract; blend until combined. Add 3/4 cup coconut oil in a thin stream through the feed tube while processor is running until smooth, thin filling forms. Pour filling into crust and place in the refrigerator until set, at least 4 hours.
Place chopped chocolate in a heatproof bowl. Heat coconut milk in a saucepan until near boiling; pour over chocolate. Whisk until smooth glaze forms. Pour over cake and refrigerate until set, at least 30 minutes more.