Hi,
Unless, for some reason, by "tag" you mean an image, link, button or so (e.g. to a brand product listing):
Many moons ago I attempted to place the brand name in front of product names in all views, carts, emails, invoice, and figured it's total overkill.
So, since then I'm advising shop owners to enter product names with the brand name included, like "XYZ Product Name". It's easy to remember and do. And, obviously, it'll then be displayed consistently everywhere without any customisation at all.
If you already have too many products to do do so manually for each one, it can be done with a single query in phpMyAdmin (or maybe even with a HikaShop mass action... I haven't checked).