Well, just because a sensor is "new" doesn't necessarily mean it's good. Was it a NTK or Denso oxygen sensor, or another brand? I've run into issues with Bosch oxygen sensors on Nissans, for whatever reason (and odd because Nissan uses a Bosch-style fuel injection system). Per the service manual, possible causes are as follows:
-Harness or connectors (the sensor circuit is open or shorted)
-Heated oxygen sensor 1
-Heated oxygen sensor 1 heater
-fuel pressure
-Injectors
-intake air leaks
-exhaust gas leaks
-PCV valve
-Mass air flow sensor
First thing I would do is clean the EGI grounds; there will be two, 10MM head bolts on the intake plenum that secure several grounds. Remove the bolts and clean-up the eyelets on the ends of the wires and the contact area on the plenum. Reinstall the grounds wires and bolts and tighten the bolts. Check for any splits in the air intake duct and make sure the clamps are tight. Make sure there are no vacuum hose leaks. Make sure there are no exhaust leaks. Confirm fuel pressure is within factory specs using a fuel pressure test gauge. Make sure the PCV valve is not stuck open and the hose is in good shape. Re-check the connectors for the Bank 2-front oxygen sensor, making sure there are no bent pins nor water inside the connectors. With the Band 2-front oxygen sensor unplugged, check the resistance between the two, outermost pins using an ohmmeter; resistance should measure 2.3-4.3 Ohms at 77 degrees F. Make sure the PCV system is in good working order and the PCV valve is not sticking open. Carefully clean the MAS with MAS cleaner or electrical contact cleaner. Erase the codes and see if it returns. If it does, then my only suggestion is download a factory service manual and follow the diagnostic procedure for code P0153 located in the "Engine Control" section. Nico Club's site has downloadable, full manuals and NissanHelp.com has downloadable, loose sections in it's "knowledge base" section.
