Combine crumbs, butter and sugar; press into the bottom of a 13-in.x 9-in.x 2-in.baking dish.
Bake at 325° for 10 minutes; cool.
Pour evaporated milk into a metal mixing bowl; add the beaters.
Cover and chill for at least 2 hours.
Meanwhile, in a small bowl, dissolve gelatin in water; chill until syrupy, about 1-1/2 hours.
Remove milk from refrigerator and beat until stiff peaks form.
In a large mixing bowl, beat cream cheese and sugar until smooth.
Add gelatin; mix well.
Stir in pineapple and 3/4 cup walnuts.
Fold in milk.
Pour over crust.
Chill for at least 3 hours or overnight.
Sprinkle remaining walnuts over the top before filling is completely firm.