As an update, after ditching the project/build tooling setup that Nesper required, I got Nim working wonderfully (with Nesper's library itself as a dependency)

As an update, after ditching the project/build tooling setup that Nesper required, I got Nim working wonderfully (with Nesper's library itself as a dependency) within PlatformIO and ESP-IDF on an ESP32 :) I even have hardware UART support and have a working SIM7000 modem connection going (though only with AT commands, not PPPoS yet, though I'm planning on that next). Nim is the future of firmware development, of that I am sure.