Combine the vanilla wafer crumbs, chocolate chips, and nuts. Add the condensed milk and mix until thoroughly combined.
Divide the dough in half. Place one of the halves on a sheet of waxed paper. Roll into a log 9 inches long and 2 inches in diameter. Wrap the log in waxed paper. Repeat with the other half of the dough. Refrigerate for at least an hour.
Unwrap the chilled cookies. Cut into 1/2-inch slices.
Notes
*I use my food processor to make fine cookie crumbs.