Describe the bug
If a FileNotFoundError occurs somewhere on module-level within noxfile.py, nox will display a misleading error:

misleading error "Failed to load Noxfile noxfile.py, no such file exists."

The problem is here: https://github.com/theacodes/nox/blob/main/nox/tasks.py#L109
This except clause is harmful. Something like this would solve the problem:

if not Path(global_config.noxfile).exists():
    logger.error(
        f"Failed to load Noxfile {global_config.noxfile}, no such file exists."
    )
    return 2

Shall I create a PR?

How to reproduce
noxfile.py:

from pathlib import Path

import nox

requirements = Path("/non-existing/path/requirements.txt").read_text()

@nox.session(python=["3.9"])
def foo(session):
    pass

$ nox -s foo
nox > Failed to load Noxfile [...]/noxfile.py, no such file exists.

Expected behavior

The stack trace of the actual error should be visible.