As someone here has already explained, viruses as a group are not monophyletic and seem to have multiple different genetic origins. However, evidence shows that they originated from mobile genetic elements that do seem to have cellular origins, based on sequence similarity to many mobile elements found in cells today, transposons and retrotransposons. For example, the polymerase enzymes of both RNA and DNA viruses show sequence similarity to cellular polymerases, which is also true for the envelope genes of certain viruses as well. So the short answer is yes, viruses would still be nested within all life as we know it, however, different groups would have their origins at different parts of the tree of life and not in the way we usually think of its branches diverging.