From al-Malfūdh Sharīf, pg 337:

Question: If a Wahābī, who subscribes to Kufr beliefs, performs a Nikah, will it be valid?

Answer: The Nikah will be valid because Nikah entails an agreement between the contracting parties, even if a Hindu were to perform it. But it is definitely Harām to employ such a person to officiate [the Nikah] because of showing respect to him. Since a Kafir is not worthy of respect, therefore it must be avoided at all times.