In large bowl, cream butter, shortening and sugars Beat in egg and vanilla.
Combine flour, baking soda and salt; stir into butter mixture, mixing well.
Stir in chocolate chips and nuts.
Drop by teaspoonfuls, 5 cm apart, onto greased baking sheets.
Bake in 180ºC oven 8-10 minutes, just until edgesare golden (centers will still be soft).
Remove to wire racks to cool.