The seal character is "cutting pavilion". This doesn't seem to be Chen Banding's seal. This seal is rare. Chen Banding doesn't seem to have the nickname "Qiting".

Chen Banding 1876- 1970), namely Chen Nian, is a painter. Yin Shan, Zhejiang (now Shaoxing) people. Born in poverty, he studied poetry and calligraphy since childhood. Worship Wu Changshuo as a teacher. After the age of 40, I went to Beijing, first working in Beijing Library, and then teaching in Beiping Art College. He is good at flowers, landscapes, calligraphy and seal cutting. He used to be director of China Artists Association, vice president of Beijing Painting Academy and president of Chinese Painting Research Association.