Message Authentication Code (MAC) algorithms, which ensure an integrity of packet messages, play a critical role in emerging Internet of Things (IoT) environment. However, IoT devices are only with very limited storage, energy, computation power. For this reason, many studies have been conducted to achieve an optimized MAC implementations on IoT devices. In this paper, we propose a compact implementation of Chaskey algorithm on the 16-bit MSP430 processor. For optimized implementation, we suggest methods including addressing mode, optimized rotation left operation, operation elimination, additional branch statement, and loop unrolling. Our implementations are fairly evaluated in FELICS Triathlon framework. In the scenario 0, the speed and code optimized encryptions are 80 cycles faster and 120 bytes smaller than previous state-of-the-art, respectively. Similarly, we achieved the further optimized results in scenario 1 and scenario 2.