Well there were certainly movements that called for the redrawing of borders along ethnic and cultural lines. To use your Nigerian example in the south east of the country the Biafra republic that roughly followed the boarders of the precolonial kingdom of the same name and the Igbo ethnic group, attempted to gain independence from Nigeria in 1967 after the 1960 independence of the country but ultimately the large Nigeria which had the backing of most of the world's great powers defeated the succession movement which only enjoyed the support of neighboring Benin and some French support. Likewise

But in more general terms while the colonial era borders caused a fair bit of long term instability a lot of leaders were concerned that attempting to redraw borders on mass would have too great a short term destabilizing affect throwing these young and fragile states into civil conflicts. As a result the UN and many African leaders supported the principle of Uti possidetis juris, maintaining the pre-independence boarders of nations by and large.

To quote from the foreword section of The Causes of War and Consequences of Peacekeeping in Africa (OAU)

At a critical moment in 1963, the Organisation of African Unity

(This was the predecessor of the modern African Union)

made a decision to accept the colonially defined borders that african states had inherited from Europe. The leaders >within the OAU did so because in the immediate postcolonial period, African political leaders focused on the reality that >post colonial states were quite fragile and could be easily destabilized. When the OAU made the decision to accept and >honor inherited colonial borders, African governments were more interested in consolidating the state than examining >the the social divisions within their own borders. To have examined the social components of nation formations would >have lead, at least in their initial estimation, to further disintegration of these newly created states.

Though there were some exceptions, particularly prior to the 63 decision. For example to use Nigeria and its neighbors again during the first world war Britain and France had split the German colony of Kamerun between them with most of it becoming French Cameroons and some becoming a part of British Cameroons. As Britain was giving up British Cameroons in 61 there was a referendum as to whether the different regions would return to be a part of a larger Cameroon or join Nigeria as the neighboring newly independent former British colony. In the end the north half was add to Nigeria and Southern half went to Cameroon. In the last couple of decade factors partly leading back to how the regional southern Cameroons government was dissatisfied with the French inspired Cameroon central government's style has lead to some fighting in the region known as the Anglophone crisis.