Despite having less raw power, Switch is close enough in performance that I'm sure just about anything on PS4/Xbone could be converted to it; with significant cutbacks in graphics perhaps, but in a recognizable and content complete state.
As I understand it, the biggest gap is in bandwidth and GPU throughput; this can be addressed through lower resolutions and reducing things like shadows, textures, ambient occlusion, polygon count, alpha effects, etc.
RAM wise we're looking at 3.2GB for games vs 5/5.5GB; a manageable disparity that can be solved by compressing or downgrading assets and optimizing data management.
CPU wise, not much of a hurdle; PS4/Xbone have twice as many cores at a higher clockspeed but their Jaguar cores are pretty rubbish even by 2013 standards so Switch's ARM A57 should be able to keep close enough pace that the gap can be close by optimization and tricks like reducing animation frames at a distance or bone LODs.