Yes. But the disease wave and the conquest are two quite separate events. The Indians were doomed as soon as there was sustained contact with any of the peoples of the Old World. It would not have mattered who showed up first: the Spanish, the English, or in an alternative universe, the Chinese, Arabs or Indians of the South Asian variety. Nor would the purposes and conduct of the newcomers have made any difference at all. This was almost 400 years before the germ theory of disease. No one understood, anticipated or intended the result. It was a staggering catastrophe, but it was inevitable unless the discovery of the Americas could have been delayed for another 400 years, or 500 to allow for the development of modern vaccinations and antibiotics.
Yes, we can link the disease wave to the appearance of the Europeans, but it was a consequence of discovery, not of the conquest per se.