The Nigerians were aboard a boat with 110 migrants. They were rescued by Aquarius, a ship being operated by MSF, 21 miles from the coast west of Tripoli. The ship will deliver the migrants, who included 18 women and one child, to Italy.
According to Reuters, more than half the migrants on that boat were Nigerians, with the rest from other sub-Saharan African countries as well as two Palestinians.
The Libyan coastguard vessels also intercepted two of the migrant boats, the first an inflatable dinghy that had broken down with 125 people on board off Zawiya, just west of the capital, Tripoli, said Ayoub Qassem, a coastguard spokesman.
The second boat was turned back off Garabulli, east of Tripoli, and had 112 people on board.
The migrants and their smugglers were trying to take advantage of calm seas as they launched a flurry of boats towards Italy.
Meanwhile the coastguard in Zuwara, a former Libyan smuggling hub west of Zawiya, said they had foiled a departure during the night and arrested some migrants whilst others had escaped with smugglers.
Libya is the main departure point for migrants attempting to reach Europe by sea. More than 600,000 migrants have crossed the central Mediterranean to Italy over the past four years as people smugglers took advantage of a security vacuum in Libya.
Since last summer the rate of departures dropped significantly after smugglers in the Libyan town of Sabratha struck a deal with the Tripoli government to halt their activities and were then pushed out of the town by rival armed groups.
Libya’s EU-backed coastguard has also stepped up interceptions, often cutting migrant boats off before they can reach international vessels that would bring them to Europe.