What could be wrong with my QX80 2014 my service engine light came on.

Way too many possibilities .. *Hands-on* diagnostic testing is required !

If the Light is not flashing. You have an "emissions control equipment failure" If the light is flashing it is recommended to have codes pulled with scan tool immediately and not drive. Shop around on ebay...etc, You may be able to purchase one and pull codes yourself which usually saves $$$ however understand that the codes represent what the "onboard computer" thinks is wrong with the car, and not necessarily the problem. This could have you replacing perfectly good parts and is recommended to have a repair shop diagnose and repair