In this work, chalcogenide glass (ChG) waveguides with sub-micrometer widths are fabricated by a hot melt smoothing and micro-trench filling method using As?S? glass and their properties on nonlinear optics are investigated. The third-order nonlinear optical property is measured by the experiment of stimulated four-wave mixing, showing a nonlinear coefficient of 14.1W?1m?1. Stimulated Brillouin scattering amplification is also demonstrated in the waveguide sample. The measured Brillouin shift and Brillouin gain coefficient are 6.25 GHz and 377W?1m?1, respectively. The experiment results show that the ChG waveguides fabricated by this method have high quality and good performance on optical nonlinearity. This paper was accepted at Applied Physics Express (Volume 13, 042005) and on-line published in March, 2020. The first author and corresponding author of this paper are Ph.D candidate Renduo Qi and A/Prof. Wei Zhang, respectively.