This work aims to achieve fairness among secondary users (SUs) in IoT cooperative NOMA-based CR transmission. We design a power allocation algorithm for secondary IoT network that ensures protection of primary system. Further, an independent battery constraint at each node is considered, and power gap among transmissions of two NOMA users is applied for successive interference cancellation. Our extensive simulation results show that the proposed framework provides excellent performance and for sufficient available transmission power perfect fairness is achieved in the rate of both the users.