Nidra is nature’s compelling to go into silence unconsciously, which gives you energy. But yogic nidra is the practice where you consciously get into silence in a meditative state. This would give you more energy and open doors to subtle dimensions. So the difference is that nidra involves sleeping unconsciously, and yoga nidra involves sleeping consciously. This deeply relaxing and guided meditation practice can enter you into a state of conscious awareness that lies between wakefulness and sleep.
During Yoga Nidra, you are guided through a series of verbal instructions, leading you into deep relaxation while maintaining a heightened level of awareness. So, when to practice Yoga Nidra? Before engaging in Pranayama and meditation, going into Yoga Nidra can prepare your body and mind. Hence, you should practice Yoga Nidra after the asana sequence so your body and mind can take time to assimilate the effects of the asanas before Pranayama and meditation.