add_filter( 'woocommerce_cart_tax_totals', 'show_zero_rate_taxes' );

function show_zero_rate_taxes( $tax_totals ) {

	if ( empty( $tax_totals ) && WC()->customer->is_vat_exempt() ) {
		$tax_totals['zero-rated'] = (object) array(
			'label'            => 'Zero Rated Tax',
			'amount'           => 0,
			'formatted_amount' => wc_price( 0 ),
			'name'             => 'Zero Rated Tax',
			'is_compound'      => false
		);
	}

	return $tax_totals;
}