On my Oct 7 flights (NW), I asked about why they had Sun Chips in the snack basket. The lead FA said: they are a PepsiCo product and they have to continue to use the PepsiCo products because of the contract that NW had with them. Since they now serve CocaCola drinks, this is how they are fulfilling their PepsiCo contractual obligations. Hence ... the Sun Chips.