England.
A nation's footballing standing must be judged by both its national team and its clubs (in European competitions); the Premier League, alongside La Liga, is the best league in the world, and English clubs are the most successful. I know that clubs have been packed with foreign players for at least twenty years now (a trend seen almost everywhere), but the record books only take the winning club's nationality into account.
As for national teams, the Nations League does not yet carry much weight. While it is true that Portugal won a European Championship, Greece also won one back in 2002; a national team cannot be judged solely on winning a single tournament.
{no channel}