I don’t know about other web-guides. Nim’s official website is made with Nim and available at Github[0], but it has become at bit more complicated after they switched to Karax[1]. Jester’s tests gives a good view on the routing procedures[2].
The official tutorials[3] are pretty good, when you get the grab on how to ”decode” them. For web development with websockets and microservices I would suggest you to have a look at the Redis package[4], and @treeform’s Websocket[5] and JsonParsing-packet[6].