No, as of the 7th of August Nigeria have not won any medals in the 2012 London Olympics.
302 Gold Medals were won at the 2012 London Olympics
Chile didn't get any medal in London 2012 Olympics. Their best results were gymnast Tomas González 4th place in both in the Floor and Vault finals.
There can be Gold, silver and bronze medals
35 medals at the London Olympics
The USA won 104 Olympic medals at the London 2012 Summer Olympics
They won 35 medals.
They did not win any medals in London
302 medals were handed out at the London 2012 Olympic Games
China won a total of 88 medals in the London 2012 Olympics.38 Gold, 27 Silver, 23 Bronze
2,300 in the 2012 London Olympics. 302 gold
The United States received 29 silver medals at the 2012 London Summer Olympics.