It is different. Generally, the PYB NANo is based on the STM32F401CE, which has less RAM and flash memory than the ESP32. So code size is limited. And there is no WiFi or Bluetooth.Is PYB NANO better than an ESP32?
BUT, being based on the STM32, timing is much more dependable. If you have a need for precise timing and fast interrupt response, the ESP32 fails totally and Pyboard (lite) V1.x and PYB Nano are the ones to go for. I'm not sure about the PYBD, since these are also based on serial flash.
Edit: I just loaded the latest image to an Espruino Pico, which also has an STM32F401, but with 396 k Flash only. Micropython works well, leaving ~50k for heap, which is more than ESP8266, WiPy1 or WiPy2. And the current consumption is 9 mA @ 84MHz.