I had a similar situation with my Nitro. It's also a 2010, and it had 150K miles when I got it last year. I got a 302 code after driving it for the first week. I decided to change the plugs, wires, and coil packs. I used the OEM NGK spark plugs, Denso wires, and Standard 'Blue Streak' coil packs. After all that, I still got the 302 code, and then I even got the multiple misfire code, which I think is the 305 code?
I was thinking about changing the injectors, just to see if that helped any, but first I tried running a couple bottles of Chevron Techron fuel system cleaner through it. I put one bottle each in back to back fill ups. I don't know if it was just a coincidence, but the all the codes went away, and never came back, for almost a whole year now. It might be worth a try.
Also, do you know what kind of plugs they put in? If you have the 3.7L, then you're only supposed to use the cheap copper NGK plugs that were used by the factory.