Instead of attaching the end of your shock cord to the nose cone, try attaching the parachute to the end of the shock cord then attaching the nose cone about 1/3 of the way down. This way you won't have the nose cone spinning around at the end of the shock cord.  This should reduce twisting and tangling of the recovery harness.

This tip is based on a post by Jeff Boldig in The Rocketry Forum.