This will depend on the facts of your situation. Venues are required to try to accommodate you, however bringing outside food into a venue may cause other issues for the business, such as food safety concerns. Businesses may, for example, want to reduce any risk that a customer could become sick from external food, which is out of their control. Pre-packaged foods, such as potato chips are less likely to carry this risk and are also less likely to be mistaken for food served by the business in contrast with more substantive foods that require reheating or refrigerating.