The only timing chain "issues" that I've heard about are on this forum. In my neck of the woods, there's not many Challengers, but a TON of RAM Hemi's running around.
Most have lived a "hard life", and the owners really like them.
This alone helped me decide on the 5.7l motor as being a "good one".
Yes, anything can happen, and that's why I bought the Chysler Lifetime Bumper to Bumper warranty. The drivetrain has the normal 5/100 coverage, and after that, the extended takes over for $100 deduct.
I'm running mine as usual, and not losing any sleep over anything on the Challenger. It's covered, and it's been a great ride for over a year now and 16k + miles