As a refresher: A package is a bunch of bees from a number of hives dumped together in a box, with a queen they don’t know. The queen is kept in her own little cage so the other bees don’t kill her because they don’t know her. To install a package: dump the bees (literally) into their new hive and leave the queen in her cage for the others to release once they’re used to her.
A nuc is a small colony–they already have a few frames of their own, brood, queen, etc. To install a nuc: Simply transfer the frames to your own hive, and dump any remaining bees into the hive. The caveat is that you have to be very careful not to squash the queen in this process.
You’ll notice during the nuc installation I’m scraping at the bottom of a couple of frames. The nuc is so full of bees that they’re out of room, so they’ve started building swarm cells. It may be too late–often, once they start building swarm cells, they’re going to swarm, no matter what you do. But it’s possible I could keep them from going, since they suddenly have more room to expand. We’ll just have to wait and see.