The responses to the news that Greta Gerwig's Narnia movies start with The Magicians Nephew makes me weep for everyone's English teachers.
"Hur, it happened first chronologically, so of course you should make that movie first" is a real failure to understand how storytelling works.
I really like The Magicians Nephew, but most of its power comes from the reader finally understanding a lot of Narnia's mysteries. Without that build up, a lot of it is just "OK, cool, someone threw a piece of a London street lamp to the ground in Narnia, whatever."
(Also, the reordering of the books to make Magicians Nephew #1 -- which is probably the real reason why it's being filmed first -- is due to a shady dude attaching himself to the Lewis estate and figuring out that he can get a piece of the pie if they now publish renumbered collections with the "definitive" order or whatever BS they're calling it.)