Preheat the oven to 375 degrees F (190 degrees C). Grease 2 24-cup-mini muffin pans with 1/2 cup melted butter.
Mix crushed pineapple and pineapple topping together in a bowl. Set aside.
Cut phyllo dough into 3-inch squares. Paint each square with remaining 1/2 cup butter using a pastry brush. Stack 4 phyllo dough squares together and gently press into the muffin tins. Drop 1 teaspoon of pineapple mixture into each dough cup. Place 3 to 4 walnut pieces in each. Fold dough together at top.
Bake in the preheated oven until golden brown, about 20 minutes. Let cool 5 minutes; gently loosen each pineapple bite with a small knife. Let cool 10 minutes more before serving.