We don’t have a big “mexican” section in the local wal-mart, but they do have the Nido powdered whole milk. Make sure you don’t get the Nido infant formula by mistake.
The Nido is on the very bottom shelf in our local store, and I almost missed finding it. Yellow can I think. Just go to Amazon and search “Nido” and you’ll see a pic. It’s more expensive to buy on Amazon though.
Here is the pic at this link. There is a Europe manufacturer also - I would prefer to buy that , but not available locally.