Is Dynamic Voltage and Frequency Scaling (DVFS) enabled by default on the Nitrogen8M Mini?

Answer

Yes, DVFS is enabled by default.  

The status can be checked by cat'ing the sysfs node below:

/sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state

This will provide the time spent in each state, thus verifying that DVFS in enabled.