Maradona posted a picture on social media showing medical staff with him at half-time of the 2-1 victory but denied that news that he had been taken to a hospital.
"I want to tell everyone that I am fine," his Instagram post read. "I was checked by a doctor and he recommended me to go home before the second half, but I wanted to stay because we were risking it all. How could I leave?"
Argentina's victory over Nigeria meant they reached the last 16, where they will face France on Saturday.