ROM Hack LayeredFS nsps? (for example Deltarune/Undertale)

[DerEineee]

Hi

is it possible to change all the contents of undertale with the contents of deltarune und repack it as a nsp file?
I mean deltarune is already running pretty well on the system.
It would be nice to have a simple "click n' start option" to play it on the switch. ^^

 

[Mythical]

Pretty sure you just need to unpack, edit game files, change titleid, and repack with hactool