2000 nisson altima timing??
 

I have a Nisson altima was driving fine then I stopped at the bank was letting my friend out I put the car in park let my foot off the brake then it just shut off on its own wouldn't turn back on now it turns on makes loud noise then after 30 seconds it starts to smoke is it the timing belt how so I fix it or how much would it cost to fix is it worth fixing?