The initial diagnosis was torn MCL, torn medial capsule and torn meniscus.
When they went in for surgery to repair those things, they determined his ACL was damaged enough to also need surgery to repair it as well.
I don't believe that second surgery specific to the ACL has taken place yet.
Adrian Peterson tore his ACL and MCL December 24th, 2011 and played in Week 1 of the following season.
Chubb himself suffered a multiple ligament tear (although not his ACL) in October of 2015 and was back playing in Week 1 of the following season as well.
Nick is obviously a maniacal rehabber, so we'll see what happens. I wouldn't rule him out for 2024 by any means, but I don't know how realistic week 1 is at this point.