while the answer to your question is no (“can I call a custom node”),
the goal you are trying to achieve is possible (“as I would like to loop it”).
Obviously, you can loop over it by feeding a list of points, but if you need to customize it (ie use different types as inputs, you can just use the code from the custom node, which is quite simple, as a function in your python code.
Example below (not tested)
fam_instance_by_point(point, famtype, lvl):
# From FamilyInstance.ByPointInView.dyf at
# make sure familysymbol is active
if famtype.IsActive == False:
newobj = doc.Create.NewFamilyInstance(point.ToXyz(),famtype,lvl)
created_instances = 
for point in points:
element_instance = fam_instance_by_point(point, famtype, lvl)