This technique is used to escape the half nelson lock.
Your attacker has you in the half nelson position as shown.
Step back slightly with your right foot and reach down with your left hand to cup the back of your attackers left ankle. Also twist your right hand so your palm is on your attackers chest.
To perform the throw just pull back with your left hand and push with your right.
This technique is used to escape the full nelson lock.
Your attacker has you in the full nelson position as shown.
Thrust your elbows down to your sides to break your attackers grip. Keep your elbows here to pin your attackers arms.
Take your right foot behind your attacker so that you are stood next to them.
Cup your hands behind your attackers knees.
Pull your attackers knees forward and up to throw them backwards. You should place your right knee on the ground.
You can now finish with a strike such as a backfist.