No, I am not joking. Die Hard = Hard Nut. Die Hard 2 = Hard Nut 2. And so on. You can imagine how much this little detail amused me and I've been quizzing D about it for ages. He revealed that it's a compliment to call someone a крепкий орешек; it indicates a strength of character similar to "He's a tough nut to crack." Don't take my word for it though- check out Potap and Nastiya's video КРЕПКИЕ ОРЕШКИ (Hard Nuts)
Awkward lyrics translation by me, forgive any errors!
Him: Movie, popcorn, I've sitting with Nastiya
Her: What movie is this? Some kind of horror film?
Him: No, this is a blockbuster, it's got all kinds of things. The Hard Nut- that's Jack, he's unstoppable.
Her: Who's that bald guy? I would fall in love with him.
Him: Dream on, that's Bruce Willis. He's the main character and he won't put up with any teasing. According to the movie, he's got the hardest nuts.
Chorus: I don't know what to do with this disaster. I was conquered by a bald-headed nut. Oh, what a handsome nose and tough glance. My man, my hero, my hard nut.
And then the song goes on with Potap recounting the entire Die Hard series for Nastiya.
Bonus info: Btw, Nastiya is a very common nickname, it's short for Anastasiya.
More bonus info: Potap and Nastiya are very popular in Ukraine and Russia. You can find tons of their music videos on YouTube. Here's a link to an interesting write-up of another song on another blog.
And one more: Want to see more of Bruce Willis in Ukraine? Go here!