Combine chocolate and espresso and place over a double boiler.
Heat on a low flame and stir until chocolate is about three-quarters of the way melted.
Remove from heat and stir until smooth.
Transfer to a mixing bowl, toss in the toasted nuts and mix well.
On a cookie sheet lined with parchment paper, spread the mix and chill in the refrigerator for about 30 minutes, or until it sets.
Break into pieces and serve.
