For singleplayer

init.sqf

private _cfg = configFile >> "CfgWorlds" >> "GenericNames" >> "AfroNames" >> "FirstNames"
_unit setName getText (_cfg select floor random count _cfg);

For multiplayer

init.sqf

private _cfg = configFile >> "CfgWorlds" >> "GenericNames" >> "AfroNames" >> "FirstNames"
[_unit, getText (_cfg select floor random count _cfg)] remoteExec ["setName",0,_unit];