A persistent claim holds that Viracocha was described as a bearded white man, and that Andean people therefore mistook the arriving Spaniards for the returning god, a story often repeated to explain the ease of the conquest. This should be treated with real caution. The bearded-white-god image and the returning-god motif owe a great deal to Spanish authors writing after the conquest, who had reasons to cast the invasion as prophesied and providential, and who were also reading their own Christian expectations into Andean belief (some even tried to identify Viracocha with a wandering apostle).
Modern scholars generally regard the "the natives thought we were gods" narrative as a colonial construction rather than reliable pre-conquest Andean belief. Viracocha the creator is genuinely central to Inca religion; the flattering legend that grew up around European arrival is a separate and far less trustworthy thing.