Not a mechanic here, but i have a 97 cavalier and went thru the same problem of stalled on my while driving, cranks but won't turn over.
I changed cam and crank sensor, fuel regulator and had compression and spark. Me and my brother then came to a conclusion the timing chain jumped. Turned out to be the timing chain tensioner broke and timing did jump. Put new timing chain and gears and tensioner in it and started right up.