Hi, welcome to the forum!
As the acceptance email tells you, “remember that not all accepted nominations will appear in all Niantic games”. This is very likely to be what you are experiencing.
As the email also tells you, you are nominating a wayspot, not a Pokéstop. This distinction is important because not all wayspots are eligible to appear in Pokémon GO, as all games have inclusion rules. Please check this post from @cyndiepooh answering someone in the same situation for more detail:
As also said in that post, to confirm for sure that this is what is what is happening, we would need the coordinates of your nomination and its title. You can find the coordinates in the submission email.