This paper proposes an efficient nested KES design for short GII-BCH codes. The polynomial updating is broken down into two steps to reduce the critical path without requiring scalar pre-computation. Besides, the KES is reformulated to reduce the number of clock cycles without incurring any area overhead. Detailed implementation architectures are also developed. For an example code over GF(2^{10}) that protects 2560 data bits with around 10% redundancy, the proposed nested KES design achieves at least 25% reduction on the area and 37% reduction on the area-time product averaged over the nested decoding rounds compared to prior efforts.