There are two kinds of nickbnames for towns, those made up by their Chamber of Commerce, and what the locals call the place.
Oakland is Oak Town. Placerville is Hangtown. Compton is the 'hood. Berkeley is Bezerkeley and People's Republic of Berkeley. West Hollywood is Boys Town. The city is "the city".
Chico is the City of Roses, but so is Pasadena. It is also the City of Trees but so is Sacramento. Gotta do better. The Ellensburg of California? Flatland?
El Cerrito has no nickname at all. Dullsville? Not Richmond?