The fictional nation of "Island Nation" is the target of the attack in Top Gun: Maverick.
The film depicts a hostile nation that is developing a highly advanced nuclear weapon program. This nation is never explicitly named, but it is clearly a stand-in for a real-world adversary, with many viewers speculating it to be a representation of Iran or North Korea.
The film's plot revolves around Maverick and his team of fighter pilots being tasked with destroying this nation's uranium enrichment facility, preventing them from completing their nuclear weapon project.
However, it is important to note that the film is purely fictional and does not represent any real-world events or geopolitical situations.