Kodali Nani is a Local Leader and also 3-time MLA. He was elected as MLA Twice on TDP Ticket and Once on YCP Ticket. All the attempts made by TDP to defeat him in 2014 hasn't yielded results due to his strong followers base, image and YCP supporters. The only thing which might work against him is the money factor as he isn't financially sound.
On the other hand, Devineni Avinash is financially sound and his family background comes in handy. Facts that he is non-local and doesn't have his own cadre/image is a big minus. He is solely relying on the TDP Factor here. Gudiwada Voters preferred Kodali Nani for the past three terms. New face of Avinash could work in favour of the youngster to some extent if the voters want a change.
Political Analysts say, Chandrababu Naidu is risking the political career of Devineni Avinash by fielding him against a strong opponent. This wouldn't have happened if Devineni Nehru was alive.