It’s true that there are several toy lines based on this. The concept of pokémon commanding giant guardians is a very popular subject, especially within the sentai genre.
(Of course, not all of them are based on the tapus. There are also several based on fossil pokémon or aegislash, both of which tend to be a little more popular than the tapu imagery. Then there was that one series wherein the robots were actually based on pyroar—that seems really popular at the moment. And finally, there’s Neon Origins Arceuseon, whose robots were based on mr. mime.)
The Pokédex According to Bill 