I don’t know how true to life the film was
It’s interesting to read the Wikipedia page for the film – there are a lot of significant aspects of Nash’s story that were just omitted or invented; e.g. Nash was apparently bisexual, he fathered a child by another woman who he abandoned, and his wife actually divorced him (they remarried years later). There’s also criticism of how inaccurately his illness and treatment were dramatised.
The film makers say they weren’t trying to tell his story literally, but when you start skipping or rewriting stuff like this it starts to feel more like a fictional drama inspired by John Nash, rather than an autobiography.