This is a typical sign of a failed DPF system on the Nissan's with the 2.0L diesel
First you could try and regenerate the system and if this fails i would have the system removed .
You are in the USA so there i have no idea who can do this for you . most likely the dealer will know
but they will first do a forced regeneration with there scan tool which will take around 1/2 hr ..
In Europe they have them professionally removed, but the ECM has to be reprogrammed ,depending on local laws
you can or can't do this .
Check the oil level as you also may find it getting higher as Diesel will be forced into the system after a forced regeneration.
If all fails and you can not have the system removed you will have to replace it .
Please rate my help a good to excellent if you are satisfied .
If not ready to rate don't rate poor or bad service as we can continue to work on this issue or I can opt out and recommend another expert .
After accepting there is no extra charge for further assistance.
If I don't reply soon I will as quickly as I can when i get back on line.
Kind regards Greg