Sub-Saharan Africa’s most populous nation was for much of the past decade its biggest recipient of foreign direct investment. These days, it trails not just Angola, but Mozambique and Ghana too. When even China’s unfussy investors are having second thoughts, you know you’re in trouble. To get a sense of why these deals keep failing, it’s worth looking at another major Chinese-Nigerian project. U.S. authorities are investigating China Petroleum & Chemical Corp., or Sinopec, over allegations that the state-controlled refiner paid Nigerian officials about $100 million of bribes to resolve a business dispute. Corruption and construction projects in Nigeria go together like jollof rice and chicken, so it’s hardly surprising to see Sinopec embroiled in these allegations — but if an $80 million engineering contract can cause problems, what about a $5.8 billion dam (see Mambilla project)? –Bloomberg/