If you don't want to eat chips with sandwiches you could eat vegetables such as carrots, celery, sliced apples or an apple that you slice yourself.
You can also eat vegetable chips that are more healthy for you or you could eat a bag of popcorn along with your sandwiches.
Even those little hot dogs in a can are great to have in your lunchbox along with your sandwiches as they make a great food to eat that fills you up along with the sandwich.
Pickles are also good to have as a snack along with your sandwiches and they keep easily in a lunch bag or lunch box.
Or you could make your own baked potato chips which are healthier than other chips are.