ARDUINO IDE debug level for stack trace only (nodeMCU 1.0)
The crash report is printed to 'standard output' by __wrap_system_restart_local in core_esp8266_postmortem.c in esp8266 Arduino core. 

The standard output is considered as debug output in esp8266 Arduino core. Debug output to hardware Serial can be enabled in runtime by Serial.setDebugOutput(true);. 

At compile time the initial debug output is controled by -DDEBUG_ESP_PORT=, for example -DDEBUG_ESP_PORT=Serial1. The Tools menu "Debug port" sets the DEBUG_ESP_PORT define. The crash report is not controlled by "Debug level" setting.