Changed the antifrieeze by draining the radiator and disconnecting the
main coolant hose.

Left the lights on and drained the battery (d'oh!!!). Recharged the
battery and drove it around the block to get coolant back in the engine
block. I was watching the temp level to see if it lowered. Never
noticed the temp level change from mid-range and the coolant overflow
container and radiator remained full. The temp gauge never ran hot or
cold.

Let the car sit for a day and now it won't start. Swapped batteries
with my truck and truck started fine with the Maxima battery.

Maxima will turn over but will not start. Is there something I might
have disconnected during the coolant change that might charge this. I'm
looking for something I did during the coolant change or battery
charge, and not non-related items like fuel pumps, timing chains, etc.

I'm a doofus and obviously not mechanically inclined, so be gentle...