Yes, everything points to Nick Bosa being ready for Week 1 (Sept. 10 in Australia). The wiki (from the Nick Bosa page) says he's "on track" for that opener, which would be about 11 months after his right ACL tear. The 49ers targeted a late July/early August return to practice, and at OTAs he was already doing field work — the tear was clean with no meniscus damage, which helps.
That said, Bosa is taking a more methodical approach this time (his third ACL tear), and the 49ers' league-low 20 sacks last season underscores just how much they need him. New DC Raheem Morris has made pass rush a priority, but at 29 with three ACL tears on his history, there's some risk baked in even if he's on schedule.