Some opposed extending Keshi's tenure as the Super Eagles coach after they failed to qualify for the recent CAF Africa Cup of Nations in Equatorial Guinea.
The 53-year-old has called for a fresh start on Tuesday at an official signing ceremony, saying any lingering bitterness needed to be put in the past.
"This is the time for us to come together to fight for this nation," Keshi said, adding: "I am begging you all to please put the past behind and let's start afresh."
Keshi's initial contract of three years ran out after last year's FIFA World Cup™ in Brazil, where Nigeria reached the last 16 knockout stages. He had previously steered the side to a win at the 2013 Africa Cup of Nations, raising his profile in Africa's most populous nation after a string disappointments at the continent's top tournament.