Re: best way to combine 5 frame Nuc with full size colony
If you mean safest by best, rather than most practical;
Shake off brood frames in front of large hive and place back above excluder on large hive. Wait until brood frames are again covered with nurse bees and a move a few to full hive where you have previously installed nuc. Move frames or boxes as fast as you are comfortable, it is not a race.
When the large hive is down to a single with proper age larva, kill the old queen and let them raise a new queen.
4 yrs, Peak 14, back to zip, T lite; godfather to brother's 3.