In BE, chips = Pommes; crisps = Kartoffelchips, always. The only time you ever hear "chips" for something crispy is with tortilla chips, but then always with "tortilla" preceding it.
Three other things to mention:
1. Crisps are not something you go out specially to get. You either get them "nebenbei" with your shopping or at the pub (or from a hotel vending machine). There's no special trip to the vendor involved, as there is with chips.
2. It is perfectly normal to eat crisps out of the packet, so there would be no reason to emphasise it as if it were a particularly wacky thing to do to distract you from the fact that your father is a homicidal child molester.
3. I admit the usage is odd. You eat chips out of the paper where I'm from, and the only place you get "packets" of chips is fast food places like KFC, Burger King and some kebab shops.
In conclusion: she's talking about Pommes.