There is no tilde. Poesía chiapanecas, for example, means the poetry of Chiapas, Autoridades chiapanecas means the persons in power in Chiapas, artesanías chiapanecas means the artisans of Chiapas--male or female. The word does not refer just to a dance. As a noun, it refers to the women of Chiapas; as an adjective, it means from or of Chiapas.