I'm woefully ignorant about African names, but I did find a few Chewa names online that might suit.
Chisomo - "baby who is a blessing"
Khumbo - "wish/baby who fulfills a long-awaited wish"
Imikizani - "to wait patiently for something"
Chawezi "Gift (from God)" would be perfect, but it looks like it's Tumbuka, not Chewa.
I can't speak for the validity of the source, but I used this preview at Google books:
http://books.google.com/books?id=56pPheM9hpMC&pg=PR9&source=gbs_selected_pages&cad=3#v=onepage&q&f=false