Well I guess one way to do it is to start by axing the resolution for the portable version down to 640x480 resolution.
That would be 1/6.75th the resolution of 1080p. Then you reduce some other assets, downgrade a few other things, cut out anti-aliasing ... and yeah ... you should have something that can run at 25-30 fps in a 160 GFLOP undocked state.
EDIT: Ubi Soft is having problems getting AC to run at 900p at 30 fps on the PS4 ... yeah, the Switch version will likely be quite ugly/scaled back in that regard.







