NEF import issues

We need lots more information.

Please tell us which camera you are using. Please tell us if you are talking about Lightroom or Lightroom CLassic. Please tell us the version NUMBER. Please tell us the complete exact word-for-word error message.

You should be able to import NEF files, I do this all the time. When you say cannot import them, what are you trying, what is failing and what software are you using (LR Classic?)