I have a hard time getting my mind wrapped around this. As has been said by others, it is hard to imagine Germany retaining its African colonies unless they came out ahead in WW1, they lost but got a very favorable peace, or there was no WW1. One almost has to imagine that a Nazi-like movement arose out of Wilhemine Germany without the trauma of WW1 - which I suppose might be possible given the general way 20th century mass movements screwed everything up.
Assuming Germany became "Nazi" in 1933 in the situation described above, the retention of colonies may not be a big emotional issue for the Nazis. Having not "lost" them, there might be far less public and Nazi interest in keeping them - especially if they could be used to buy off other nations (the UK and France, mainly) in exchange for a more favorable attitude toward Germany's aims in the east.