Traditionally Chinnamsta is shown as a red nude figure, in a dancing posture with her own severed head and blood flowing into her own mouth and either the mouths or kapalas of Vijaya and Jaya, her two companions. All three as ascetic females wearing little but jewelry
Her "Vahana" is Kama and Rati shown in Pahari painting as copulating
There are numerous modern interpretations including her as essentially also sa brandishing Durga's knife (to slay the buffalo?) and occasionally with other figures in attendance.
In Nepal the traditional for occurs in both Hinduism and Buddhism and in the latter she is is specifically an aspect of Vajravarahi.
I know of no traditional images of her on a Lion and only one by a modern artist, Kailash Raj, Cited below at
exoticindiaart.com It might be interesting to ask him if he has a traditional source for the iconography.
John
John C. Huntington, Professor Emeritus
Buddhist Art, Asian Numismatics,
Field and Object Art Photography