The nicinfo utility operates slightly differently than under io-net:

Note: Ported *BSD drivers may not support the nicinfo ioctl.


To get stats on legacy io-net drivers running under the shim the following are equivalent and are unchanged from the io-net behaviour.
# nicinfo -r en0
# nicinfo /dev/io-net/en0
To get stats on a particular native driver.
# nicinfo wm0