To make the cutout even easier skip all the tying and check out these bars!Assuming the top bar doesn't take the same size combs as the nuc, then the standard method for the last 150 years is to do a cutout. make frames for the top bar hive, cut the combs to fit and tie them into the frames for the new hive. But this means you have to build frames to fit. Anything else is more trouble than it's worth, in my opinion.
But then I'd build it to take the frames, or just buy a package. Why buy a nuc with they are on the wrong sized combs anyway?