TBE, it would hardly constitute an expansion - these are aeroplanes we already operate now! They would be unlikely to be as intensively used by Virgin Nigeria, at least to start with.
Oyindo, this isn't about any tit-for-tat protectionism. Air Nigeria had some very dodgy engineering and operation practises towards its end, and, as I understand it, lost their approval to fly to and over the UK and US (and maybe all other ICAO countries, for all I know). Before Nigerian-registered aircraft are allowed to operate internationally again, the airline and the Nigerian authorities will have to show that such practises will not recur. Hence, a period of successful, safe domestic operation is likely to be necessary before other countries accept that those particular demons have been slaughtered.
Had the Nigerian authorities had any argument with the treatment of Air Nigeria, any retaliation they might have attempted would have happened at the time. BA and Virgin have been operating to Nigeria continuously since (and before) the Air Nigeria problems, and there is no reason to suspect that that will change. Remember, Virgin Nigeria is happening at the request of the Nigerian government..