>>2937039
>pls give me a rundown how to use 2 nanos in a fashion where i get around that serial on the underside of the board
Just follow any Arduino as ISP tutorial:
https://docs.arduino.cc/built-in-examples/arduino-isp/ArduinoISP/
Pic especially related. All the same data pins (D10,11,12,13) still go to the ICSP header on the target. The only difference when using a Nano instead of an Uno as the source, is that you probably need a capacitor from the source's reset pin to ground. 1-10uf should be good, only add the cap after you've written the sketch onto the source arduino. If you plan on doing this a lot, I'd recommend soldering a ribbon cable to the host machine with 2x3 IDC connector on it.

The missing IC is the USB-to-serial converter (and the voltage regulator, in case you're running on 7-15VDC input). Without the IC you can't program it via the USB port, or send serial messages over the USB port.