What is the ruling on naming children with names such as: Malak, Nancy, and Taqi?

It is not appropriate to use names like "Malik" (King) and "Taqi" (Pious) because they involve self-praise. As for the name "Nancy," it is preferable to replace it with something better because it has no meaning, unless it is a foreign name free of prohibitions, in which case it would be permissible. The most preferable is to choose the names of prophets and companions.