In this article, a field‐plated and recessed gate III‐Nitride Nano‐HEMT developed on β‐Ga2O3 substrate is proposed and investigated for various performance characteristics over different temperatures. The 2DEG (Two Dimensional Electron Gas) dependence on temperature is critical for commercial utilization of GaN‐based HEMTs (high electron mobility transistors). Here, the temperature influence on 2DEG for proposed HEMT over the range of 300–400 K has been investigated. The results demonstrate that the 2DEG density of proposed HEMT reduces as temperature increases. It has been observed that phonon scattering results in a sharp decline in the mobility of 2DEG as temperature increases, which causes the electric field to decrease. It also exhibited that the cut‐off frequency decreased over the temperature changes from 300 to 400 K due to diminution in electron mobility. This research aims to contribute an extensive overview of proposed III‐Nitride Nano‐HEMT designed on a lattice‐matched substrate of β‐Ga2O3 to foster future research on the latest developments in this field.