Are you using the wider tires on stock wheels? The vehicle I replaced the 2015 QX60 was the 2013 Nissan Pathfinder which is basically a similar platform with our QX60. On stock wheels of my then old Pathfinder, I ran 255/50/R20.Sanjman,
If you want to the car to handle better put on bigger tires I am currently running 265 50 20 on she drive a lot better then stock 235. only bad thing I notice is gas mileage will suffer .. I am getting 19.2 mpg on the normal mode and 17.5 on eco .. That is the price you pay if you want the car to handle better. you can check out https://tiresize.com/calculator/ that will show you how much side walls you are getting and losing ..
I am interesting to go wider tires when it's time to buy new tires.