Orange(ish) throat, indication of chest-band, whitish belly & devided tail leaves three possibilities:
1) Barn Swallow
2) Red-chested Swallow
3) Ethiopian Swallow
I am leaning towards Ethiopian due to the relatively pale orange throat, however, this is very hard to judge from a photo (perhaps you noticed?). If you noted the colouration of the underside of the tail, the ID is rather easy. Similarly, if you noted the the exact shape of the dark chest-band. I am not aware of any records of Red-chested from Nigeria, but distribution comes close, so I wouldn't be surprised.