Bmw e87 n43b16a

Bmw e87 2008 with n43b16a engine came in with engine light on and no smooth idle in some cases (at stop lights)and in first few meters on acceleration from stop as customer states.i couldn't verify the erratic idle at the moment, only I read the following fault codes. I believe it's the nox sensor but I would like to take an other opinion because it is quite expensive part. Thanks