This paper investigates observer-based networked control for stochastic nonlinear systems under false data injection (FDI) attacks and limited communication bandwidth. To mitigate the impact of FDI attacks while reducing communication load, we propose an FDI attack-resilient periodic encoding–decoding scheme based on uniform quantization. We first establish a detectability criterion for the stochastic nonlinear system under this periodic encoding–decoding scheme. Then, we derive a condition to further guarantee the input-to-state stability of the resulting closed-loop system. The condition, which enables the determination of the desired observer and controller gains, involves a series of linear matrix inequalities that are straightforward to verify using available MATLAB numerical tools. Finally, we validate the effectiveness and robustness of the proposed controller design through a case study.