There are no such things as unicorns or ghosts.

There are no such things as unicorns nor ghosts.

Which sentence is correct?

The first.

"Nor" is usually used as a correlative conjunction, in company with "Neither."

The first is correct.

Both sentences are grammatically correct, but they have slightly different meanings.

The first sentence, "There are no such things as unicorns or ghosts," implies that unicorns and ghosts do not exist. It is stating that neither unicorns nor ghosts are real.

The second sentence, "There are no such things as unicorns nor ghosts," also conveys the idea that unicorns and ghosts do not exist, but it uses the word "nor" to emphasize the negation. The use of "nor" is more formal and can create a stronger sense of denial.

In summary, both sentences are correct grammatically, but the second sentence may express a stronger sense of denial due to the use of "nor."