I don't rest the rear of my tailpiece on the nut. Remember the tailpiece wire loops over the end pin collar, up over the nut. Others might want to start from here on their comments. The Saddle is located at the bottom of the instrument,that's what the tailpiece wire goes over, and it serves to reinforce the top table, which would most probably crack if the full tension of the strings were applied to it. The nut is at the top of the neck.
Many basses use steel cable instead of tailpiece wire, which is more adjustible and flexible.