Has there been any historical battle which became so universally well regarded, that military academies from across the world would would study it? Or are most military academies inherently biased towards studying battles in their own national history?
One classical example would be the Battle of Cannae, when Hannibal annihilated a larger Roman army. His unreservedly successful double envelopment on that day have since been regarded as one of the greatest displays of generalship in history. In addition to Cannae, several ancient battles have a reputation for being still studied at military schools worldwide.
Modern military academies such as the École Polytechnique [sic] in Paris, the U.S. Military Academy at West Point, the Frunze Academy in Moscow, and the Royal Military Academy at Sandhurst continue to study and analyze famous ancient battles (Marathon, Thermopylae, Plataea, Leuctra, Chaeronea, Gaugamela, Cannae, Zama, Pharsalus, and Adrianopolis) and sieges (Syracuse and Alesia).
- Grafton, Anthony, Glenn W. Most, and Salvatore Settis. The Classical Tradition. Harvard University Press, 2010.
Note: The Ecole Polytechnique does not aim anymore to train officers. The Ecole Spéciale Militaire de Saint Cyr in Brittany is the one responsible for it.
Since they were fought during antiquity, these battles have no real substantive link to most modern nations, but are nonetheless analysed as examples of tactical brilliance. A curriculum might very well be more focused on the national or regional history, but frankly it is a bit nonsensical to think that the nationality of the participants would define whether an engagement is or isn't a great (in terms of execution) battle.
In addition to examples from ancient history, many other battles have been very highly regarded. For example, Napoleon's career, including his greatest victory at the Battle of Austerlitz, was studied as far as as the Army Military Academy in China.