Accessing the navigationController from a 'push'ed viewcontroller?

Question

I've got a main menu using a UITableView which can successfully push and display other ViewControllers to the fore. However, within these pushed controllers I wish to be able to push other controllers onto the navigationController stack. self.navigationController in a pushed ViewController seemingly does not reference anything, so when I do [self.navigationController pushViewController:nextVC animated:YES]; nothing happens. What am I doing wrong?