How can I properly connect a BLDC motor, ESC, battery, and servo to Jetson Nano for motor control? What are the necessary connections and precautions?
I cannot answer this, but some info to get you started…
First, Jetsons are quite sensitive to power regulation. If your power supply is in any way coupled to what the BLDC uses for power, then the system will fail (instant shutdown most likely, possibly power spikes could damage the Jetson). Jetsons are full computers and not just a microcontroller and proper shutdown and surge protection are rather important; power regulation on the Jetson is much more significant than it is on a PC motherboard.
Second, you have to give a specific type of hardware to ask how a Jetson can handle it; different controllers and servos use different protocols. Even if you only have a specific controller as a thought, and you do not yet have it, then an exact model might be useful to look at because it will have specs on its requirements (e.g., i2c, serial UART, or SPI communications, voltage levels, so on).
FYI, various protocols and voltage levels occur on different hardware, and even a Jetson has a possibility in places of using 1.8 V, while usually it is 3.3 V. It just depends.