The Nazca (about 100 BCE to 800 CE) left no writing system, so no text records their own speech. The Quechua and Aymara families dominant on the Peruvian south coast today arrived through Inca imperial expansion in the fifteenth century and Spanish colonial administration afterward, six hundred years or more after Nazca civilization had already ended, so their modern presence cannot be read backward onto the Nazca population. Scholarship on Andean historical linguistics treats a Quechuan or Aymaran tie for the pre-Inca south coast cultures as speculative, resting on colonial-era impressions of multilingualism that may equally reflect internal variation within those two families elsewhere in the Andes.
What would resolve this A securely dated Nazca-period inscription would settle it outright, but none has been found and the culture is understood to have had no writing system at all. Short of that, a documented layer of loanwords or toponyms in a later, attested language that can be traced specifically and exclusively to the pre-Inca Rio Grande de Nasca drainage, rather than to the wider post-Inca Quechua-speaking Andes, would be evidence a historical linguist could evaluate.
OpenHistorical linguistics, archaeologyWillem F. H. Adelaar with Pieter C. Muysken, The Languages of the Andes