Upvote:2
This is not a typo and does not invalidate the visa.
The US does not use special characters (those other than A-Z) for names in their visas. They have their own scheme for translating special characters into non-special ones which typically involves removing the special parts of characters, such as the snake above the "N" in this name.
As a reference, you can see this in the US visa FAQ for Germany (https://de.usembassy.gov/visas/visa-faqs/) in point 1. I could not find a similar FAQ entry on the respective page for Spain, but the same rules should apply.