Create a New Location with RENDER

Use this in Write Node

import os

if not os.path.isdir(os.path.dirname(nuke.thisNode()['file'].evaluate())): os.makedirs(os.path.dirname(nuke.thisNode()['file'].evaluate()))

Plus info about eval(Evaluate):

>>> your_calculation=input("Enter a calculation:")

Enter a calculation:12*52

>>> eval(your_calculation)

624