Protector and helper of expatriates from Kastaniani Saint Nicholas is especially honored by the villagers and the main parish church has his name. This imposing church, is built on the model of Athens Cathedral, was built in 1928 on the site of an earlier church of 1802. It has rich exterior and interior decoration. Among other stands the arched main entrance with sculptures and carved iconostasis work of Charalambos Skalistis from the village of Tournovo (Gorgopotamos). One of the most significant icons of the old church which is kept in the newer church is the Adoration of the Magi dating back to 1630 and St. Nicholas picture with 7 other bearing the date 1773.
For its building worked the best craftsmen from Kastaniani and hewers. Among the latter stood two, Costas Gossios (Giortolis) and Kostas Tzoumakas who also edited the three-arched portico distyle entry which displays similarities with Zosimaia School in Ioannina. Just above the entrance stands the cancerous inscription “ΝΙΨΟΝ ΑΝΟΜΗΜΑΤΑ ΜΗ ΜΟΝΑΝ ΟΨΙΝ: (Wash [the] sins, not only [the] face) while the decoration is complemented with an elaborately carved relief tendril.