The Swacchao! series are sitting Nendoroids.  They are sold as a whole Nendoroid or as only a lower half with a chair.  All Swacchao chairs use the same sculpt and paint job and come with a peg to secure the Nendoroid to the chair and double-sided stickers to affix the chair to places like bookshelf ledges.  See last photo for instructions on how to assemble the chair for use on a ledge.

Marisa Kirisame 2.0 Swacchao (Sitting Nendoroid) of Touhou Project

https://www.goodsmile.info/en/product/11319/Nendoroid+Swacchao+Marisa+Kirisame.html

Marisa Kirisame 2.0 Swacchao (Sitting Nendoroid) Parts Set of Touhou Project

https://www.goodsmile.info/en/product/11320/Nendoroid+Marisa+Kirisame+2+0+Swacchao+Parts+Set.html

This was made to coordinate with Marisa Kirisama 2.0 Nendoroid (#1348).  This chair is identical to Reimu's chair.