How would this feature be useful?

It'd save a few keystrokes and would work as a default for --pythons.

Describe the solution you'd like

Check for NOXPYTHON environment variable:

NOXPYTHON=3.11 nox -s tests
NOXPYTHON=3.10,3.11 nox -s tests

While we're at it, it might make sense to also add env vars for --extra-pythons and --force-pythons.

Describe alternatives you've considered

Continue using --pythons, or include the Python version in NOXSESSION, i.e.

NOXSESSION=tests-3.10

but this couples the default session with a Python version

Anything else?

No response