2019 Chevrolet Tahoe back wheel came off driving driving on interstate shattering back windshield

Friday, I was traveling home with my two year and we had been gone all day. We got off a ramp onto the interstate and made it about half a mile before I switched lanes to pass a trailer in tow and I heard my back windshield shatter and my 2019 Tahoe Z71 dropped and I lost control and had a hard time steering and realized I had lost a tire and saw it jump the median into oncoming back. I was going maybe 45 mph when this occurred. ( first picture is off where the tire came off and the back right tire was bent inward towards the inside of the car) (second picture is where the tire came off and somehow hitting the lift gate and shattering the back window before running over the median.)
This car has been in the shop twice for a stabilitrak problem and 4 weeks ago I had a flat on the tire that came off and I got it fixed and never had a problem or I thought other than the tire monitoring systems reverse reading after the tire got fixed.
The Chevrolet dealership is trying to tell me a wallowed out single lug nut caused this accident and my insurance company is wanting to investigate what caused the accident because they said they had been getting other calls of this problem happening to others.
The dealership then tried to start replacing parts without the approval from the insurance company and was got very hostile. I do not believe that a wallowed out lug nut caused this accident. But I am not a mechanic and I am in the process of getting my car towed to a non affiliated Chevrolet body shop to get a second opinion. I have tried to add pictures of the damage.
Is there anything else other than a loose/wallowed out lug nut that could have caused this accident?