Question

How does Major Kovaloff believe his nose came to be removed from his face?

Answer 1

Major Kovaloff believes that witchcraft is what took his nose.

He knows a woman that wanted to marry her daughter to him, but he had often rejected. He thinks that to get her revenge, she "must have hired some witches to spirit it away," which is the only way he could think his nose could have possibly disappeared. 

Answer 2

In "The Nose" by Gogol, the protagonist wakes up to realize that his nose is gone. Major Kovaloff cannot explain this to himself, and he is extremely confused and embarrased. He eventually reaches the conclusion that the nose must have left his face due to witchcraft, and he attributes this witchcraft to the mother of a girl he knows. He has been flirting with this girl for a while without proposing, and he assumes that this has infuriated the mother. However, when he contacts her, the mother denies any involvement.