Chips at 9pm is a little ...ummm... rash.
However I have problems in that direction as well.
Better things to eat at 9pm could be cold meat (such as sliced beef or cooked chicken), cheese, hard boiled eggs.
I find that when I am motivated I beat down the carb cravings and eat something more sensible, such as the above.
It helps to have a stash in the fridge.
I also suffer from a lifelong feeling that a sandwich is a good snack or meal.
I try and just have the filling now, but again I don't always succeed.
Please don't panic over your first few days with the Libre 2.
It will give you an overview of what your body does over 24 hours and may suggest the best times to eat as well as the best things to eat.
You may be having false hypos if you are bringing your BG down below long term levels, so again don't rush into anything.
Your body may settle down after a bit of lower carbohydrate eating.