If you're referring to the professor Chinua Achebe, I found out that you should pronounce his name as follows
/'ʧɪnuɑː əʧə'beɪ/
(or if you're not familiar with phonetic script) tsjin-u-ahh-tsjuh-bay
Source: YouTube -- at 0:25 his name is uttered. Hopefully this was helpful. Regards Jordy