Is Nigerian eligible for layover without visa

No, there will be no issues. If you arrive into Guangzhou by a direct flight from a country different than the Philippines, you will be definitely eligible for 24 hour visa free transit and you do not need any kind of visa, guaranteed. Also, you will be surprised, but you will not cross any immigration or customs controls, but you will just cross a security check and you will basically walk from the exit of your plane that you have arrived into Guangzhou to the gate for your flight to Manila. Nothing more than that. You are perfectly free from any formality and from any requirement.