The Super Eagles raced into a four-goal lead before the half-hour mark, but the Leone Stars scored on the cusp of halftime and added three more after the break to claim a dramatic point away to the three-time champions.
The result moves Sierra Leone up to third in Group L while Nigeria remain in top spot on seven points, four clear of Benin who host Lesotho on Saturday.
The Super Eagles doubled their advantage through the in-form Victor Osimhen in the 21st minute. Zaidu Sanusi provided a pin-point cross to the feet of the Napoli forward who made no mistake from close range.
Iwobi completed his brace six minutes later with his speculative effort catching the Sierra Leone goalkeeper completely off guard and two minutes later the hosts were 4-0 up. Samuel Chukwueze dazzled the Leone Stars defence before finishing with aplomb as Gernot Rohr’s men looked well on their way to all three points.
The Leone Stars took confidence from Quee’s strike and scored a second in the 72nd minute as Al-Hadji Kamara nodded home from close range.
Sierra Leone continued to boss proceedings and pulled within one goal with 10 minutes remaining as Mustapha Bundu rattled the back of the net. Kamara duly completed the comeback in the 86th minute with his second of the game as the Leone Stars claimed a remarkable result that will long live in the memory of those involved.