You can build pretty much anything in VNL
But the question is what precisely you need, and thus how easy it may be. Do you have a reference, or an example?
Assuming you mean nanorod is the same as nanowire, have a look at using Builders>Nanowire in the Builder. For instance, take Si from the Database and open this plugin, specify a radius and the relative surface energies and press Preview. You don't need the numbers to be correct, the only thing which matters is the relative ratio between 100, 110 and 111 to get the desired shape.
