ZURICH—Food group Nestle is expected to post organic sales growth of 7.1 percent for 2021 on Thursday, almost twice as high as the year before thanks to strong demand for coffee and pet food, but high input costs will start taking a toll on profitability. Markets will focus on the guidance for this year, especially on the KitKat and Nescafe maker’s ability to raise prices without endangering volume growth and market shares. The outlook for coffee, the petcare business, and plant-based food that benefited during the pandemic will be scrutinized. Any indication the company could further reduce its stake in cosmetics group L’Oreal, maybe to finance a large acquisition, would also make headlines. Organic sales, which strip out currency swings and acquisitions, are expected to rise by 7.1 percent in the full year, including a 5.2 percent rise in volumes and a 1.8 percent increase in prices, according to a …