Summarize:

Sometimes you will have a singular verb paired with a plural verb in the same sequence. Look at the noun closest to the verb (usually the noun following "nor") to determine the tense. If this noun is plural, make your verb plural. If it is singular, make the verb singular. If you're in doubt, read the just the second noun and the verb aloud to see if it sounds right. Incorrect example: "Neither they nor he are interested." Correct example: "Neither they nor he is interested." Incorrect example: "Neither he nor they is interested." Correct example: "Neither he nor they are interested." When "nor" sets off a dependent clause, no comma is necessary. Similarly, a comma is not necessary if "nor" is only used to draw a relationship between two nouns. If it sets off an independent clause, however, you should proceed the "nor" with a comma. A dependent clause is a sentence fragment that relies on the rest of the sentence to be complete. An independent clause contains both a subject and a verb, and as a result, it could be separated from the rest of the sentence and still stand on its own. Correct example: "No one knew the answer, nor did they make a guess." Incorrect example: "No one knew the answer nor did they make a guess."
Look at only the second noun if the tenses are mixed. Use a comma when "nor" sets off an independent clause.