Ms Williams took up post on 17 January, succeeding Dr Susan Atkins who had carried out the role since 2008.
The Service Complaints Commissioner (SCC) is an important part of the service complaints system, and as Commissioner, Ms Williams will provide an alternative point of contact for service personnel and others (such as family members or friends) who, for whatever reason, do not have the confidence or are not able to raise allegations of bullying, harassment, discrimination or other improper behaviour directly with the chain of command.
Ms Williams will have the power to refer these cases to the chain of command for action and be notified of the outcome.
She will also provide independent assurance on the fairness, effectiveness and efficiency of the service complaints system to the Secretary of State for Defence by way of an annual report which is laid before Parliament.
Ms Williams was appointed following open competition and a rigorous selection process which was chaired by an independent assessor from the Commissioner for Public Appointments.
Defence Minister Anna Soubry said:
I am pleased to welcome Nicola Williams to this post, and I have no doubt she will hold us firmly to account for delivering an armed forces complaints process that is fair, effective and efficient.
Independent oversight is an important part of the complaints handling process.
It is fulfilled at the moment by the SCC, with the Ministry of Defence currently taking a Bill through Parliament to further strengthen the role into that of an Ombudsman.
The Armed Forces (Service Complaints and Financial Assistance) Bill, currently going through Parliament, enables the creation of a Service Complaints Ombudsman and makes changes needed for reform of the service complaints system.
Ms Williams will in the first instance take on the role and current powers of the SCC and then, once legislation has been enacted and following approval by the Queen, will take up the role of Ombudsman with the increased powers.
Nicola Williams had, since 2009, held the post of the Complaints Commissioner for the Cayman Islands with a remit that extends over 93 government entities.
Since 2009 she has also been a Crown Court Recorder sitting on the London and South Eastern Circuit.
Between 2004 and 2009 she was a Commissioner at the Independent Police Complaints Commission with particular responsibility for Kent, Sussex, the Ministry of Defence Police and part of the Metropolitan Police.
She had previously been a board member at the Police Complaints authority. Between 1985 and 2001 she was a barrister in private practice and specialised in criminal law.