In my Twitter feed, a video available at MoMA (Museum of Modern Art, New York) showed up. In it, I was surprised by several things, but relevant to this forum, there was a billboard advertising "Washington Crisps," which I found surprising. An NGram search shows that chips has long been a more favored usage in American English (and likely the corpus size causes American English to dominate all English), though far less so in the case of potato chips.
What's notable to me about the "potato" variation of the phrase "potato chips" is the enormous spike around WWI.
I can't find a plausible explanation for this spike. What is your best explanation?