Installation probably isn't too bad. According to the Factory Service Manual there are only 4 "pawls" holding the cowling in place behind the rear view mirror. There are a couple electrical connections back there. The mirror itself can be twisted to release it from the mount.
The hard part will be sourcing a mirror. Based on what I'm seeing, the QX30 mirror has a MSRP of $560 and even at discount parts vendors it's fetching $350-400.
Thankfully My "Premium" trim came with HomeLink, from the factory; otherwise I'd just use a 3rd party garage door remote.