ñaña

sister, especially a liked one; sister; older sister; a female relative, such as a cousin or aunt, with whom one has a close affective relationship; nursemaid, wet nurse

“Ella no es mi prima, es mi ñaña.” — She's not my cousin, she's my sister.

Borrowed from Quechua ñaña. Most senses likely influenced by nana.

ailment (especially when exaggerated or simulated); feces

“Él siempre está con muchas ñañas.” — He is always whining about his ailments.

Likely a babble word of separate origins.