TLDR: it's for getting North Korea to stop using nuclear blackmail against other countries and taking unheard of steps towards denuclearization and peace.
Though the author doesn't appear to realize that Trump didn't win a 2020 peace prize because he was nominated for the 2021 prize based on when he was nominated.
Hijacking to post an article about his 5th nomination
TLDR: it's for getting North Korea to stop using nuclear blackmail against other countries and taking unheard of steps towards denuclearization and peace.
Though the author doesn't appear to realize that Trump didn't win a 2020 peace prize because he was nominated for the 2021 prize based on when he was nominated.