Place 1 1/2 cups chocolate chips in microwave-safe dish. Microwave 30 seconds on high, stir and continue to microwave in 10- to 20-second intervals, stirring after each, until chocolate is melted and smooth. Set bowl aside and cool to room temperature.
In medium bowl, whisk together flour, cocoa powder, baking soda and salt. In large bowl, beat butter and both sugars using electric mixer until light and fluffy. Add melted, cooled chocolate and vanilla, blend until fully incorporated. Add eggs, one at a time, beating well after each addition. Add flour mixture slowly; mixing until incorporated. Fold in chocolate chunks, nuts and mini marshmallows.
Fill pint containers with cookie dough and refrigerate up to 4 days or freeze up to 1 month. When giving as a gift, attach following baking instructions:
Preheat oven to 350°F. Drop dough by rounded tablespoons, or using small cookie scoop, onto parchment-lined baking sheets, about 1 inch apart. Flatten dough slightly using back of spoon.
Bake 10 to 12 minutes, until edges are lightly cracked but centers are still soft. Remove from oven and cool slightly on baking sheet before transferring cookies to wire rack to cool completely.