Nominal Condition as the name suggests is a condition which exists only in name while the actual condition might vary. In Lean parlance, nominal conditions define the acceptable working conditions of a process or a machine even though the actual working condition might vary. For e.g. the nominal voltage for electricity in India is 220V, but it actually varies between 220V±10%.
An application-oriented question on the topic along with responses can be seen below. The best answer was provided by Vastupal Vashisth on 14th January 2019.
Applause for all the respondents - Prashanth.