@Satyam Chauhan
I think you can use the service tags ,AzureIoTHub is servcie tag .
Below is the list of service tags with ip ranges.
https://www.microsoft.com/en-us/download/confirmation.aspx?id=56519
To add a service tag you may need to use azure cli as i believe the azure portal do not support adding service tags.
az network nsg rule create --resource-group myResourceGroup --nsg-name myNSG --name RDP-rule --priority 300 \
--destination-address-prefixes '*' --destination-port-ranges "AzureIoTHub " --protocol Tcp --description "Allow RDP"