I don't know how related this is to Nairobi and your work, but since a few days the news here report attacks by terrorists to Christian churches in the North town of Garissa, near the border with Somalia.

The Kenyan government sent troops against the Al Shabaab rebels in Somalia during the last year and those seem to be making retaliatory actions in Kenya, or at least they are officially blamed. I don't know how much this is motivated also as inter-religious struggle. Considering how easily a tourist/foreigner can be accused of being an agitator/criminal by a crowd in a witch-hunting expedition I would avoid places of worships of any sort at the least suspect of tense religious relations in town.

The situation in Nairobi can obviously be totally peaceful. Actually the situation in Garissa can also be totally peaceful and the attacks to the churches of the last days being maybe an isolated occurrence. Ask around, read the local newspapers. If there are dangers of inter-religious clashes take all precautions.