"The toe is not an issue," Wambach told AP. "Toe, head, whatever. I don't really care. I'll play with a broken bone."
Sweden tied Nigeria, 1-1, in its opener.
The USA's tie against North Korea was only the second time the Americans failed to win a first-round game at the Women's World Cup. It tied China, 3-3, in Sweden '95, where the Americans finished third.
Wambach scored the first goal against North Korea, which scored both of its goals while she was being treated on the sidelines.
Nigeria is a five-time African champion.
The USA beat Sweden 3-2 in each of their last two encounters.