I'll start this off by saying, no, it has not been confirmed, and as such, it should not be added to any pages on the wiki. This is purely speculation.
What we have been told is that the game takes place in Africa, and the specific nation it takes place in is in the midst of a civil war.
The new trailer shows us many things, one of which is the nations leader, another is it's flag.
The flag is clearly based on the Pan-African flag, in fact it is the Pan-African flag with a yellow image on top. The image appears to be some kind of big cat but that isn't necessarily relevant. The colours in the flag are used on a number of other (mostly African) flags. A list of these can be seen on the page linked above. The most important one of which is the Flag of Biafra.
The Republic of Biafra was an independent nation that split from Nigeria in 1967. The nation is once again part of Nigeria and has not officially existed since 1970. There is however movements to bring it back.
How does this relate to Rising? Well, as mentioned above both the nation in MGR and Biafra use the Pan-African flag. On each of those flags is a yellow image, in Rising it appears to be a big cat of some kind, Biafra on the other hand featured a RISING sun on its flag. Not only that, but the national anthem of Biafra was called Land of the Rising Sun. Its lyrics spoke of battles and bloodshed. There were civil wars when the nation split from Nigeria, this may be happening again in Rising. Now, Rising may not be based around Biafra, but perhaps another new nation trying to split from Nigeria.
Just something to think about.