Change sign-in instructions for Azure portal

Updated instructions to sign in to the Azure portal instead of the preview portal.

Author: aimee-littleton

articles/nat-gateway/quickstart-create-nat-gateway-v2.md

@@ -58,9 +58,7 @@ Create a resource group to contain all resources for this quickstart.
 
 ### [Portal](#tab/portal)
 
-1. Sign in to the [Azure preview portal](https://preview.portal.azure.com).
-> [!NOTE]
->  StandardV2 SKU NAT Gateway can be deployed through the Azure preview portal only at this time.
+1. Sign in to the [Azure portal](https://portal.azure.com).
 
 1. In the search box at the top of the portal enter **Resource group**. Select **Resource groups** in the search results.