In small bowl, dissolve espresso powder in boiling water. Set aside to cool. Heat oven to 375°F. Spray 9-inch pie pan with nonstick cooking spray.
Place wafer cookies in food processor bowl with metal blade; process 10 to 15 seconds or until crumbs are fine. Add cut-up cookie cakes; process 10 to 15 seconds or until fine. Place crumbs in sprayed pan. With spoon, press in bottom and up sides of pan.
Bake at 375°F. for 5 minutes. Cool in freezer or refrigerator.
Meanwhile, spoon frozen yogurt and powdered sugar into food processor bowl with metal blade; process 10 to 15 seconds or until yogurt is slightly softened. While machine is running, gradually pour dissolved espresso through feed tube and process an additional 10 seconds or just until blended.
Quickly spoon mixture into cooled crust; spread evenly. Sprinkle with nutmeg. Freeze at least 1 hour or until firm. If desired, garnish with chocolate coffee beans.