The easiest way to start your trial is to prepare a chitosan solution and mix it with ZnO nanoparticle aqueous suspension with various ZnO vs. chitosan ratios. To facilitate the coating of chitosan to ZnO nanoparticles, you could try bath or probe sonication of the freshly prepared mixture.

@Sijie

The problem is chistosan is said to be soluble in acidic environment. So in general it is dissolved in 5% acetic acid solution but at the same time, I am doubtful that when mixed  ZnO can be decomposed into Zn2+ ions in acetic acid(5%). 

Yes is soluble in acid enviroment. Stiring speed is also important. Sonication is also important. We also use nitric acid.

Read this please

http://www.sciencedirect.com.sci-hub.cc/science/article/pii/S1466856416304581

Chitosan powder is dissolved in 0.5 % acetic acid to prepare  chitosan solution. Solution is kept over night with stirring  until all chitosan powder is  dissolved.Then, ethanolic ZnO uspension  is added with stirring to the chitosan solution to obtain chitosan-ZnO nanocomposite