The movie, "Nichiren And The Great Mongol Invasion"

According to the historical account in this movie https://www.youtube.com/watch?v=0Vh1kBx8CCo it was Nichiren who was responsible for putting an end to the Mongol invasion and saving Japan - spacetreasury

um...dude? It's a movie O_O Not a documentary.

The Japanese title was "Nichiren to moko daishurai" and it was released in 1958. Here is part of a review:

The first question for me was if the film was going to be stiff and stagey. The answer is yes, but in an enjoyable way. The production is excellent and typical of the 1950's Japanese cinema. Well directed. Katsu is ernest but very hammy in a thankless role. How do you portray a real man who is implied as having powers over lightening and typhoons? Raizo Ichikawa portrays a young deputy Shogun but he never really gets to act in anything but a sitting position. The film has a number of melodramatic moments and also departs from the historical record. While depicting Nichiren's unrelenting dismissal of all other Buddhist sects, the film skips some other controversial aspects of his beliefs. The special effects are excellent with some great ship miniatures.

Once again we have a religious film preaching peace but manages to include lots of bloodshed and death. An interesting film for many reasons but I can't recommend it to an average viewer.

If you're going to use a movie as your evidence that something happened a certain way, expect to get laughed outta Dodge. Really. It is dangerous to be that gullible. We don't even know who funded it or suggested that it be made in the first place. Here is an excerpt from another reviewer comment:

Among the historical inaccuracies following may be mentioned: 1. Nichiren visited his mother in 1264 and not vice versa as shown 2. The Mongol invasion occurred after his return from Sado and not before as shown, nor was it the reason for his pardon from exile. The ending borders on the ridiculous. It is difficult to discern the POV of the film-maker. Most objectionably, he has made the protagonist, through his persistently grim teeth clenched lack of human expression, look more comic than anything else.

Keep in mind, the first biography of Nichiren was written by someone who was born the year after Nichiren died. And it contains no material beyond what's already found in Nichiren's letters. For that matter, while Nichiren Shoshu and the Soka Gakkai/SGI feel that only legitimate, authentic letters in Nichiren's own hand exist, scholars have classified many as inauthentic, copies, and forgeries.

Nichiren was unknown to history. No one who knew him wrote anything about him. No one outside of the religion wrote anything about him. All we have is sectarian propaganda from people who never even met him. Here is a review article on the subject for anyone who's interested.