Has -Responsive actually made the chart responsive for you?
$Data = 1..10 | ForEach-Object {
$item = Get-Random -Max 1000
[PSCustomObject]@{
Name = "Test$item"
Value = $item
}
}
New-UDNivoChart -Bar -Keys "value" -IndexBy 'name' -Data $Data -Height 500 -Responsive -Layout horizontal