Starbucks said on Tuesday that Brian Niccol, chief executive at Chipotle, would be the coffee chain’s new CEO – just over a year after current boss Laxman Narasimhan took over the role. Narasimhan steps down as chief executive and as a member of the Starbucks board “with immediate effect,” said the company in a statement. Starbucks shares were around 21 percent higher in early afternoon trading, while Chipotle Mexican Grill shares fell by about eight percent. The leadership shifts come as Starbucks pushes to turn around its business while contending with broad-based sales declines in its most …