In a small bowl, combine graham cracker crumbs and melted butter. Set aside ½ cup; press remaining crumbs into a 15x10x 1-in. pan.
Make the dessert:
Slice bananas and layer over crust. Cut ice cream width-wise into ten slices; place over bananas. Spread edges of ice cream to cover banana slices, and form a smooth layer. Sprinkle with nuts. Cover and freeze until firm, about 1 hour.
In a large saucepan, melt chocolate chips and butter; stir until smooth. Pour over ice cream; freeze until firm, another hour.
In a large bowl, whip cream until stiff peaks form; add powdered sugar and vanilla and mix. OPTIONAL to use 2 cups Cool Whip (don't add powdered sugar or vanilla.)
Spread whipped cream over chocolate layer. Top with reserved crumbs. Freeze! (will keep for several weeks).
Remove from freezer about 10 minutes before serving. Cut into squares and enjoy! Optional to top with a strawberry or fresh fruit.