is cuban slang meaning "here it is/ this is it" - with the suggestion of having reached the best or ultimate, therefore you do not need to look anywhere else. Probably originally from spanish "aqui nada mas".
The phrase is heard in Cuban/salsa music, eg after some great words, music or dancing.
during a song... you can hear someone shout out... Ahi Nama!!!!
You know it is a hot tune. Sonorra Carruseles
have a song that uses this phrase repeatedly.