Here are some words that start with those prefixes:
* Nom-
* Nominal: Relating to a name or names.
* Nominally: In name only.
* Nomenclature: A system of names used in a particular science or art.
* Nominative: Relating to the grammatical case that indicates the subject of a verb.
* Nominat-
* Nominate: To propose someone for an office or position.
* Nomination: The act of nominating someone for a position.
* Nominator: A person who nominates someone.
Let me know if you had a specific word in mind, and I can help you find it!