I'm not sure what the feature is called, but Google seems to collapse all accented letters to their base character when indexing. So a search for "Nandor" will find a record "Nándor". But searching my Civi database for the unaccented name finds no results. Is there a setting (either in CiviCRM or MySQL) or a plugin that would make such searches work?
This feature exists. It is part of MySQL and called collation. You can read about the background on https://dev.mysql.com/doc/refman/5.7/en/charset-collation-effect.html .
In my test database a search on Nandor returns Nándor. Reason
last_name column is defined as
`last_name` varchar(64) COLLATE utf8_unicode_ci DEFAULT NULL COMMENT 'Last Name.'
and the collation
utf8_unicode_ci defines them to be the same.
Altering the setting with
ALTER TABLE civicrm_contact MODIFY last_name varchar(64) COLLATE latin1_bin;
has the effect that they are not considered the same anymore.
What is your collation setting?