Advice on file encryption

[bibi21000]

I am here to ask for your opinion and advice for file encryption.
I am developing a program to store my personal and confidential information in a digital safe.
The biggest part of the work is done but now I need to choose the "cryptographic parameters".
Here is what I did: https://github.com/bibi21000/NaclFile/blob/f0d13d2d297d8949bc006de2878984bddb9738aa/naclfile/__init__.py#L63

What do you think?
Is it "strong" enough for file encryption?

Any feedback is welcome :)