Backscatter communication (BackCom) has been emerging as a prospective candidate in tackling lifetime management problems for massively deployed Internet-of-things (IoT) devices, which suffer from battery related issues, i.e., replacements, charging, and recycling. This passive sensing approach allows a backscatter sensor node (BSN) to transmit information by reflecting the incident signal from a carrier emitter without8 initiating its transmission. To multiplex multiple BSNs, power domain non-orthogonal multiple access (NOMA) is fully exploited in this work. In this paper, we present the design and analysis of a NOMA enhanced bistatic BackCom system for a battery less smart communication paradigm. Specifically, we derive the closed-form bit error rate (BER) expressions for a cluster of two devices in a bistatic BackCom system employing NOMA with imperfect successive interference cancellation under Nakagami-m fading channel. The obtained expressions are utilized to evaluate the reflection coefficients of devices needed for the most favorable system performance along with the performance comparison with orthogonal multiple access-time domain multiple access scheme (OMA-TDMA).