** Shares of chip designer Nvidia NVDA.O fall 2.2% to $173.84 premarket
** China's market regulator says it will continue investigation into NVDA after preliminary findings show co violated country's antitrust laws
** Regulator claim NVDA's acquisition of Israeli chip designer Mellanox Technologies violated terms of Chinese market regulator's 2020 conditional approval of that deal
** Separately, China launched discrimination and dumping probes into US chips on Saturday
** U.S. and China are set to continue talks on trade in Madrid for a second day
** 60 of 66 brokerages rate the stock "buy" or higher, five "hold" and one "sell"; median PT is $210
** Up to last close, NVDA up 32.4% YTD compared to a 20.5% gain in the Philadelphia SE Semiconductor Index .SOX