A lot just in general about how Duncan and Kim's friendship has grown thanks to this series. Kim had even admitted once that prior to even starting The Apprentice, she didn't know Duncan all that well, and yet here they are now.
After a combination of Nano discovering and making the hang gliders and then their incredible one jump glide from Baked Bean Fort all the way back to their base, Lalna gifts Nano a sapphire, and or the rest of the series right into the new Flux Buddies rebrand, she always keeps it in her inventory.
Everything surrounding their attempt to get to the moon has shades of this; first Lalna lets Nano fly the rocket, and does everything he can to reassure her that she can succeed and get her ready. And then, even more heartwarming, is Nano's reaction when she succeeds in landing perfectly, turning it into a Moment of Awesome too. Lewis even types in from whatever he's doing to congratulate her.
Nano: I'M NOT DEAD!
A minor example from the same episode; Lalna gives Nano his own chestplate because she didn't have one.
After Lalna having been captured by the Magic Police, Nanos rage and determination to go free him from their prison. The heartwarming really kicks in when Lalna says with absolute faith that Nano will come save him - and when she does, she is fairly grouchy (Tsundere), but he tells her he missed her.
Flux Buddies 2.0
Nano's special sapphire that she always kept on her in the previous series has now been made into a necklace. And it's the only one on the entire servernote With some help from the server admin..
Nano realizes fairly quickly someones posing as Lalna in episode 50 of Flux Buddies 2.0. She eventually exposes the fake for who he is, and carefully breaks out Lalna from where he was tied up.