This article investigates the secrecy performance of a hardware-impaired secure rate-splitting multiple access (HIS-RSMA) network in multiuser multiple-input single-output (MISO) Internet of Things (IoT) scenarios over Nakagami- m fading channels. Closed-form expressions for the secrecy capacity (SC) and secrecy outage probability (SOP) are derived and validated through Monte-Carlo simulations. The proposed analytical framework explicitly accounts for the joint effects of non-ideal hardware (NIH), imperfect successive interference cancellation (SIC), and imperfect channel state information (CSI), thereby providing a realistic evaluation of secrecy in IoT networks. Numerical results reveal that NIH has a negligible impact on the secrecy of the common message but significantly degrades the secrecy of private messages at high transmit powers. Moreover, both NIH and imperfect SIC introduce non-vanishing SOP error floors, while imperfect CSI at the eavesdropper can substantially enhance secrecy. The number of transmit antennas and the operating frequency are also shown to critically influence secrecy performance. Overall, the findings highlight that HIS-RSMA is a promising solution for secure and efficient transmission in IoT networks, underscoring the need for joint optimization of transceiver design, antenna configuration, and physical-layer security strategies in beyond fifth-generation (B5G) wireless systems.