To link your NIN using USSD, dial *109#, enter your NIN 11 digit number then you should get a message informing you if it was successful. Dial *996# to verify if your NIN has been linked to your number; to link your NIN and also to check for NIN regristation centres. To confirm if your Airtel number has been linked to your NIN, dial *1211#, you would get a message prompting you that your NIN has been successfully uploaded.