If you're looking for anime similar to Code Geass: Nunnally in Wonderland, you might like these titles. All recommendations are made by Anime-Planet users like you!
Miyuki, a normal Japanese schoolgirl, wakes up just in time to embark on the most unusual trip she'll ever take: a non stop journey to Wonderland! Along the way she'll meet up with a purrfectly sinful Cheshire Cat, a Chinese take on Tweedle-dee and Tweedle-dum, the scariest Queen of Hearts you'll ever encounter and a score of other beautiful women as she delves into the rabbit’s hole... in the middle of the sidewalk!
If you watched this OVA because you like Alice in Wonderland, then I would suggest you also check out Miyuki in Wonderland. Both are just inspired by the original book, with more focus being put on the outfits than anything else (like the plot, which is barely there). Also, the character designs for both of these anime were done by CLAMP!