Heat oven to 375°F. Sift together flour, cocoa, baking powder and salt.
Beat butter in large bowl until smooth and creamy. Beat in brown and granulated sugars until light and fluffy. Beat in eggs, 1 at a time. Beat in vanilla.
On low speed, beat flour mixture into butter mixture. Stir in hot coffee. Fold in M&Ms and chopped nuts.
Drop by heaping tablespoonfuls onto ungreased baking sheets.
Bake in 375°F oven for 8 to 11 minutes or until set. Let cool slightly on baking pan. Transfer cookies to wire rack to cool completely.