If Beasts is able to bring in north of $75 million, that would put it in the Opening Weekend range of the middle Harry Potter films, Order of the Phoenix ($77.1 million opening) and the Half-Blood Prince ($77 million).
Those movies pushed their domestic grosses near the $300 million mark, though as is the expectations with Beasts, they made a fortune overseas.
It’s fair, I think, to make comparisons to the Harry Potter films, even though Fantastic Beasts is a prequel (of sorts) that takes place in the wizarding world created by author J.K. Rowling, but has no characters that carry over to this story… yet.