This seated Surya is most probably from Nepal. The identification of Surya is based on the two lotuses he is holding in each of his hands. The crown and facial features, especially the eyes, suggest Nepal as the origin.
One of the features to note is the long sacred thread running from his left shoulder to his left thigh, pedestal and all the way back. Very long sacred thread. One other feature to note is the way hands are raised and are at a higher level than the lotuses. Normally the lotuses are at a higher level. See the example from the Pala period.
The Vigraha is solid cast and is heavy for its size. But for the engraving on the crown and the lotuses, the Vigraha is plain while retaining the presence. See the backside.
The Surya vigraha is about 8 cm in height and may date to the nineteenth century or a bit earlier.