This would be extremely welcome news. Local multiplayer has always been Nintendo's bread and butter, so being able to keep using controllers from the previous system is a huge boon. Also means not having to invest in a new 'Pro' controller hopefully.
The version of the grip that you buy as an accessory (HAC-012) can charge the joycons. However the pack in one (HAC-011) can't.
Looking around, it appears that Nintendo have also released an official "Joy-con charging stand (2-way)", suspiciously it seems they only launched it in October 2024, when various 3rd party chargers have been around for years.
There's also the official AA battery packs. Yes, really.
Hmmm, I wonder if the Nintendo charging stand will charge the NES Joy-Cons, cause the BestBuy stand I have won't (no big deal currently, the switch is usually on the dock and I charge the NES controllers on it)