When you are raised by narcissists or toxic people nature versus nurture is not really a debate because both were choatic messes. Nature refers to the genes you inherited and nurture refers to the environment you experienced. Both of these contributing factors need to be addressed in narcissistic abuse recovery.
Nature, being the genes you were born with, is not on your side when you are born into a narcissistic family. Toxic people do not take care of their health on more than a surface level. So being their offspring means you need to address these health issues. Heavy metals, parasites, and gut flora are some of the things that we inherit from our parents that have a large impact on the quality of our lives. All mental disorders are thought to begin in the gut. Cleaning up your microbiome is a great place to start when recovering from narcissistic abuse. Do a heavy metal cleanse, parasite cleanse, and start colonizing the good bacteria in your gut. These are all things that seems really simple, but after you begin to address these issues you start to realize how dynamic they really are.
Changing your environment is the easy part. Anyone can move and start over, but not everyone realizes nurture encompasses changing the way you react and respond to life. Changing your behaviors that reflect in your environment is changing your deep rooted programming. You were programmed by a toxic person who installed viruses into your programming that will cause you to self destruct. If you do not address these viruses and out of date programming it will lead to a whole system break down: emotionally, physically, mentally, and spiritually.
Nature versus nurture is not the question when recovering from narcissistic abuse. Genes and environment are both issues. The question is have you addressed both to fully encompass your healing in a holistic manner.