Check for spark and fuel, one of the two will be absent :-)

The most likely culprit for a sudden no-start on these modern engines is
either a dead electric fuel pump (whether due to a relay or the pump
itself), failed auto-shutdown relay, or a bad cam/crank sensor. You'd
need a scan-tool to check to see if the computer is getting cam/crank
sensor pulses, but you can rule out the ASD relay and fuel pump relay by
temporarily swapping in a known-good relay (I usually use the high-beam
headlamp relay). You should also hear the fuel pump whirr for about a
second or two when you first turn the key on, and if its working a fuel
pressure gauge attached to the fuel rail will tell you so (they're cheap
at any auto parts store, and attach with a schrader-valve fitting- easy
for the DIYer).

Good luck!

We had that on a 99 300M.  Had it towed to the dealer where it started.
That was about 5 or 6 years ago and it never happened again.

My theory was that the factory anti theft system was temporarily confused by
my Toyota Avalon key.  I don't think the Chrysler manual mentions it but the
Toyota manual does.  If you have 2 chipped keys and the wrong one gets too
close to the ignition switch the car may not start because it thinks the
wrong key is being used.