What is the meaning of a failing test with NOx(ppm)

check iac valve suplly or mechanical stuckup

It does have an EGR valve

You engine came with EGR, here is a picture of it, make sure it is functional.

I would replace the catalytic converter.

Google what ever your Emission Report has on it

CO or NOX

ppm ---parts per million
NOX--Oxides of Nitrogen

fist i would like you to post the year make and model of the truck along with the HC ppms and NOX ppm it would be very helpful but high hc and nox can be attributed to a faulty EGR system nox is produced when the combustion chamber temperature gets too high so a small amount of exhaust is cycled back into the air stream to help cool them there are other causes but without looking at the levels its much harder to say

means that the hc,co2,nox, emissions are too high, you will need the numbers in ppm on the read out to begin diagnossis

It sounds like you need a tune up and to clean the injectors take care of all the performance issues before you even begin the smog my suggestion would be plugs and wires and 100% that it can be your O2 sensor that is why your not passing that cost about $40 to $160 at a parts store and $40 to $90 to install good luck

High NOX readings indicate a somewhat lean condition IE: hot exhaust. Possible causes are cracked and leaking vacuum lines or lazy oxygen sensors. If possible have a reputable garage with engine electronics scanner services check the sensor to see if its helping to create the lean condition