This is prime deep fried learning pun territory...
(And really interesting problems can be really boring to work on, and really interesting companies can have a lot of cruft and technical debt under the hood.)
Their GitHub page (https://github.com/Nordstrom) doesn't have much in the way of internal projects, but it has lots of forks that will give you an idea of some of the tools they used.
https://serverless.com/blog/rob-gruhl-serverless-event-sourc...
Here's a recent talk from KubeCon/CloudNativeCon: https://www.youtube.com/watch?time_continue=5&v=xZO9nx6GBu0
Being forward thinking in tech has helped them a lot with regards to being able to move pretty fast on new things. At the same time, a website as old as theirs has a LOT of legacy.
Unfortunately, as this was before the OSS boom that came later, we probably will never see these solutions out in the open.
Seeing down thread they were big DevOps adopters changes my mind of how I saw them as stodgy. Too bad I dislike pretty much all they sell!