Here's an example of a Sherlock-inspired outfit as worn by Victoria, one of the ladies behind Set to Stunning:
The prizes are available in different tiers in order to encourage participants to put together some geek-inspired outfits all month long. For example, if you participate for 1-10 days, you're entered to win in the Prize Tier 1 group. If you participate all 30 days of November, you're entered to win in the Prize Tier 4 group. The prizes get bigger the more days you participate, and Set to Stunning has gathered an impressive list of sponsors for #Nerdvember, including: Guild Jewellery, Black Milk Clothing, Espionage Cosmetics, We Love Fine, and Her Universe. Fancy, no?
What counts as a geek-themed outfit?
"Full geek ensembles are HIGHLY ENCOURAGED, but at a minimum you must be wearing at least one (1) piece of geek clothing/jewelry/accessory to qualify. If you’re wearing an “inspired by” look (i.e. Disney Bounding or Console to Closet type looks), please include a photo of the inspiration in your pic post or at least an explanation of how your outfit is geek themed."
Full cosplay doesn't qualify.
You can read all the rules at Set to Stunning. Even if you're not up for participating, you can search the #Nerdvember hashtag on Instagram for plenty of outfit inspiration.