Filter Advanced Custom Fields Plugin Select Field with all created menu, modify "field_name" with the name of the select field.

acf_filter_select_menu

function tdp_filter_field_with_menus( $field ) {
	// reset choices
	$field['choices'] = array();
 
 	$menus = get_terms('nav_menu');
	foreach($menus as $menu){
		$field['choices'][ $menu->slug ] = $menu->name;
	} 
 
    // Important: return the field
    return $field;
}
add_filter('acf/load_field/name=field_name', 'tdp_filter_field_with_menus');