Melt over hot (not boiling) water, the chocolate chips and vegetable shortening.
Stir until melted and mixture is smooth. Remove from heat. Pour 1/2 of melted chocolate
into greased 8-inch square pan and spread evenly.
Refrigerate until firm, 15 minutes.
Return remaining chocolate mixture to low heat.
Melt caramels and butter with water over low heat, stirring until smooth. Stir
in nuts until well blended. Pour into chocolate-lined pan. Spread evenly. Refrigerate
until tacky (15 minutes).
Top with remaining melted chocolate and spread over caramel filling. Return to
refrigerator and chill until firm (1 hour).