In this paper, the exact closed form expression for the Level Crossing Rate (LCR) of the signal-to-noise ratio (SNR) at the output of the wireless system with multiple transmit and receive antennas is derived. We considered the case where the receive antennas use maximal ratio combining (MRC), and the transmit antenna that maximizes the MRC output SNR ratio is selected. The case of Nakagami-m fading channel is analyzed, where all branches are independent, power-balanced, and fading parameters of different branches may be mutually distinct. The analytical results are validated by simulations.