That is what the promo says; and, that is what it is as we found out during our recent visit to Nainital!
The tourism office is a good place to start; I especially loved their pamphlet which among other things contains a map of all trails and roads making it easier to go on treks.
We loved the boating trips in the lake (and the sail boat is an experience that is very different from the rowing and paddling boats), the visit to the zoo, the treks to Tiffin top, Naina peak and Hanuman Garhi, and the visit to Kilbury.
We also happened to spot a Eurasian golden oriole in Delhi on our way up. Several times, we also spotted a bluish green bird of the size of sparrow in Nainital and surrounding regions, whose name I do not know.