The first missing feature is the ADAS. Very recently, the XUV300 Facelift was spotted with ADAS Module, and it’s possible it could limited ADAS features such as Lane Departure Warning, Forward Collision Warning, Lane Keep Assist, and few more. However, it unlikely it’ll get Adaptive Cruise Control.
The Nexon misses on the 2-zone Climate Control which at the moment even the other rivals of XUV300 aren’t offering, so that makes it somewhat special.
Nexon misses out on Rear Disc Brakes which is a useful feature when for example you're driving at high speed, and you had to all of a sudden hit brakes, the Disc Brakes will stop way too early than the Drum Brakes.
The 4th feature it misses is the panoramic sunroof. Mahindra is stepping the features game by offering another first-in segment that no rivals will offer anytime soon.
Last but not the least, sunglass holder, which may not be a big feature, but still the Nexon in the update fails to offer.