Jose, based on this:
I have one website "My Brand" only one centralized URL domain for my customers, multiple stores for (USA, Europe, and Latin America) and three views for each stores (Spanish, English, Portuguese)
I assume that structure of your Magento instance looks like this:
You have 50 SKUs - all assigned to Main_Website (in Product in Websites tab on product edit page)
What you need to do in order to have different catalog per store is to create 3 Root Categories - one per each Store.
Then you can create different category tree (or the same) under each Root Category and assign different products to different categories under each Root Category. This way you can manage different catalog per each Store.
Here is official documentation of Root Category for Magento 2 - https://docs.magento.com/m2/ce/user_guide/catalog/category-root.html
Additionally, in "multisite" setups you need to remember about planning your structure in relation to Payment Methods, Shipping Methods, Base Currency etc. as they require separate website if you want to configure them differently for different countries (they can't be different in scope of one website). Good explanation about differences between Magento website, store and store view can be found here -> http://qatribe.pl/differences-between-magento-website-store-and-store-view/