3 cups semisweet chocolate chips
1 can (14 oz) sweetened condensed milk
1/4 cup butter
1 cup chopped nuts (optional)

Place chocolate chips, milk, and butter in large microwaveable bowl. Zap for 3-5 minutes, stirring twice during cooking. Stir in nuts.

Pour into well-greased 8X8 baking dish (9X13 for a double batch)
Refrigerate until set (2 hours)