So this is what I've been building for the last couple of days. (Helped that Andrew sent me back some of my older mosaic plates, because I really needed to steal some pieces from them.) This is a scene from the Skybound season where Jay and Nya get back together at the end of it, which is one of my favorite scenes. However, the background in the screenshot was meh, so I swapped it out for a more unique skyscape shot of Ninjago City, including Borg Tower.
As for interesting techniques used here, I used some SNOT designs to get the eyes and mouths right on their faces. Plus, while the characters are made using bricks, the background is made using plates, which add some depth to the image. (The white wind circle is actually two plates tall.) The most challenging part of this was the medium azure background; I was able to fill in a lot with larger plates, but getting all the corners filled in took some effort and whipped out my supply of 1x2 and 1x4 plates in the color.
Anyway, I'm pleased with how it turned out, and it'll show up at Bricks Cascade in 2018. Probably won't sent it on he BioniLug circuit, since it's not quite Bionicle related, but I haven't seen too many Ninjago mosaics so maybe this'll stand out.