Note: The nationalities and leagues of players and managers are displayed on their cards.
Another technical aspect to keep in mind here is that you don’t always have to match the nationality or league of your manager to the majority of your players.
For instance, if around 8 of your players already have a chemistry of 9-10 because they are from the same league, it is a better decision to opt for a manager whose league matches the remaining three players.
And like in the case of player position, you can apply a League Modifier Card if your manager and players do not have same league.