AI generated answer (using internal Slack threads):

In NetSuite, the tax code for a transaction is determined by the Nexus of the transaction, which is based on the Subsidiary and the shipping address. In your case, where a Canadian entity is issuing a Sales Order for a sale to a customer based in the United States, with both the billing and shipping addresses in Texas, you would typically use a tax code that represents an export from Canada to the US. However, the specific tax code to use can vary depending on your company's tax setup and requirements. If you are using a tax engine like Avalara, it should automatically calculate the appropriate tax based on the transaction details. If you are manually setting the tax codes, you might use a tax code that represents a zero-rated or exempt export, as goods exported from Canada to the US are generally not subject to Canadian GST/HST. Please note that this is a general guideline and the actual tax treatment can vary based on a number of factors. You should consult with your tax advisor or a NetSuite professional to ensure you are using the correct tax codes for your specific situation. ****** Disclaimer: This response was generated by an artificial intelligence assistant based on previous conversations from multiple Slack channels, and may contain inaccuracies or mistakes. ******