The only possible link to nutrition, that I see, for PTSD is to heal the adrenals. Any kind of chronic as well as traumatic stress is going to hit the adrenals very hard. It is the adrenals, in part, that cause the fight or flight anxiety attacks. The constant surge of adrenaline and cortisol is hard on the adrenals and in turn can affect other parts of the body leading to chronic fatigue as the sex hormones become affected too. The thyroid also might be affected via the HPT (hypothalamus-pituitary-thyroid) axis reaction to stress
I don't think treating PTSD just nutritionally is going to solve the problem. In this case treating wholistically, mind, body and spirit would prove more helpful. EFT, meditation and perhaps rapid eye movement therapy in addition to treating the body to help it cope with the stress with nutritional support.
I am by no means an expert on PTSD or the HPT axis. I am however hypothroid and dealing with adrenal fatigue. I have met other folks online dealing with severe adrenal fatigue to the point they need hydrocortsone because their adrenals have become depleted. Those low adrenal folks suffer panic attacks and horrifying heart palpitations. Those are two major physical symptoms of PTSD, so to me, it stands to reason that PTSD suffers need to support their adrenals.