If you want to auto-import every new video from a specific Youtube channel as a new WordPress post, you can use WordPress Auotmatic plugin which is capable of auto-importing from Youtube, here are the steps or directly check the video tutorial on Youtube

1- Create a new Youtube Campaign

2- Set the channel URL

3- Disable the keywords option to import all videos

4- disable the caching option which will make the plugin grab the latest list of the videos every run