I got the same notice for my Credit Card, this is worrying me a little bit. It's my favorite higher end dept store.
I read through everything and it appears we're safe but the change was in the financial interest of Nordstrom. They sold their credit debt to a commercial bank just the same as when a person consolidates their debt in order to stay afloat and not go through bankruptcy in order to clear their debt. The debit card is still under Nordstrom because it doesn't involve credit which further prove Nordstrom is not doing well financially thus the reason for this change.
However they did make a change to how the Notes are used and now they are treated as credit vs money. For example when you earn a $20 note when you use it, it is considered credit so when you return the item you will no longer get your note back but it will be apart of the over all credit back to your card. So say you bought something for $80 and a $20 note made it $60, if you return it you're going to get the entire $80 back on your card vs $60 and a $20 note.
So from now on I'm going to be more conscious on what I spend my notes on and I'm going to start saving them and letting them build up and use them on more expensive items vs just using them on something that really doesn't need it.