If you preorder Little Nightmares 3 on PSN, Xbox, or Steam, you get Little Nightmares 1 Enhanced Edition for free now.
Otherwise it releases as a separate purchase for all platforms on October 10.
Switch 2 seems to be a grey area at the moment as preorders have not opened for the Switch 1 or 2 version of LN3 at all yet. It stands to reason that there will probably be a similar deal for Switch 2 when preorders
do open eventually, but who knows what the hold up there is, maybe because they are still working on the Switch 2 version of Enhanced Edition or maybe Nintendo has some marketing tied to an upcoming Nintendo Direct before preorders go live. Hard to say. Or maybe Switch 2 owners will just not get it for free at all.