Alibaba Group could be a steal of a deal at its current valuation.If you're thinking about buying shares of Nvidia now, one issue you might be finding it hard to get around is its valuation. While the chipmaker's growth prospects are undoubtedly amazing, is the stock really worth paying more than 70 times earnings for? For many investors, the answer has been a resounding yes -- the chipmaker's market cap is up by around 150% this year to $3 trillion.But if you're worried that Nvidia's high valuation could l ...