Final release date TBA, but at least we know the format and have a window
http://www.nintendoworldreport.com/news/60427/alan-wake-remastered-officially-confirmed-for-switch
The story of Alan Wake is coming to the Switch - officially.
In a 12th anniversary video (embedded below), the first minute shows off-screen footage of the remaster running on a Switch Lite. Remedy later confirmed that the title would launch this fall, natively (not a cloud title) but digital only.
The ESRB listed a Switch version with the remastered version's rating when the remaster released on Xbox One and PlayStation 4 last October.
The full video, which includes an update on the TV show, is below: the Switch portion is in the opening minute.