The oil company's colors, at least in 1963, were indeed green and white, the colors on the bag. I will forward your picture to the Oil History Group in the hopes that one of them might know more. My first guess was that the chips were a gift item associated with the New York World's Fair, but that opened in 1964, not 1963.

Cities Service was restyled as CITGO (and then red and orange pump colors were added to the green to spice things up) with a triangular logo. Citgo became part of the Venezuelan National Oil Company (PDVSA) which generally is considered a "bad boy" in the USA. You'll get a now-you-see-it now-you-don't view of the old logo at its website: https://www.citgo.com/

I think CITGO is still marketed in the northeastern and Texas area of the USA. The fuel used to be available at all 7-11 Stores across the country that offered gasoline, until debranded at a lot of them (esp. on the West Coast) some years back.