The tobacco mosaic virus was discovered in 1898. That was long before nano-technology was even imagined. Also, as we still do not have any real nano-tech capability, I doubt very much that anyone could have done it then. See this link.
As far as I know the closest we have come to creating artificial life is the bacterium that Craig Venter's team created. They took a Mycoplasma mycoides cell, removed its DNA and then inserted an artificially built DNA and let the cell reproduce again. The DNA was essentially the same as the bacterium's, but with some minor changes, including a "watermark" to prove that the reproducing DNA was indeed the artificial one. Note that it still needed the rest of the cell to work. This article shows more details and also mentioned that the first artificial virus was created in 2003.