HSRP never requires interface tracking, it is just a nicety. NX-OS does support HSRP interface tracking just like IOS does, but interface tracking is considered mutually exclusive to vPC peer gateway. vPC peer gateway allows for a device to forward frames destined for its vPC partner even if it is not the active HSRP router. Scince most people really want vPC peer gateway functionality they do not configure interface tracking.
